This is Hansen et al’s end of year summary for 2009 (with a couple of minor edits). Update: A final version of this text is available here.
If It’s That Warm, How Come It’s So Damned Cold?
by James Hansen, Reto Ruedy, Makiko Sato, and Ken Lo
The past year, 2009, tied as the second warmest year in the 130 years of global instrumental temperature records, in the surface temperature analysis of the NASA Goddard Institute for Space Studies (GISS). The Southern Hemisphere set a record as the warmest year for that half of the world. Global mean temperature, as shown in Figure 1a, was 0.57°C (1.0°F) warmer than climatology (the 1951-1980 base period). Southern Hemisphere mean temperature, as shown in Figure 1b, was 0.49°C (0.88°F) warmer than in the period of climatology.
Figure 1. (a) GISS analysis of global surface temperature change. Green vertical bar is estimated 95 percent confidence range (two standard deviations) for annual temperature change. (b) Hemispheric temperature change in GISS analysis. (Base period is 1951-1980. This base period is fixed consistently in GISS temperature analysis papers – see References. Base period 1961-1990 is used for comparison with published HadCRUT analyses in Figures 3 and 4.)
The global record warm year, in the period of near-global instrumental measurements (since the late 1800s), was 2005. Sometimes it is asserted that 1998 was the warmest year. The origin of this confusion is discussed below. There is a high degree of interannual (year‐to‐year) and decadal variability in both global and hemispheric temperatures. Underlying this variability, however, is a long‐term warming trend that has become strong and persistent over the past three decades. The long‐term trends are more apparent when temperature is averaged over several years. The 60‐month (5‐year) and 132 month (11‐year) running mean temperatures are shown in Figure 2 for the globe and the hemispheres. The 5‐year mean is sufficient to reduce the effect of the El Niño – La Niña cycles of tropical climate. The 11‐year mean minimizes the effect of solar variability – the brightness of the sun varies by a measurable amount over the sunspot cycle, which is typically of 10‐12 year duration.
Figure 2. 60‐month (5‐year) and 132 month (11‐year) running mean temperatures in the GISS analysis of (a) global and (b) hemispheric surface temperature change. (Base period is 1951‐1980.)
There is a contradiction between the observed continued warming trend and popular perceptions about climate trends. Frequent statements include: “There has been global cooling over the past decade.” “Global warming stopped in 1998.” “1998 is the warmest year in the record.” Such statements have been repeated so often that most of the public seems to accept them as being true. However, based on our data, such statements are not correct. The origin of this contradiction probably lies in part in differences between the GISS and HadCRUT temperature analyses (HadCRUT is the joint Hadley Centre/University of East Anglia Climatic Research Unit temperature analysis). Indeed, HadCRUT finds 1998 to be the warmest year in their record. In addition, popular belief that the world is cooling is reinforced by cold weather anomalies in the United States in the summer of 2009 and cold anomalies in much of the Northern Hemisphere in December 2009. Here we first show the main reason for the difference between the GISS and HadCRUT analyses. Then we examine the 2009 regional temperature anomalies in the context of global temperatures.
Figure 3. Temperature anomalies in 1998 (left column) and 2005 (right column). Top row is GISS analysis, middle row is HadCRUT analysis, and bottom row is the GISS analysis masked to the same area and resolution as the HadCRUT analysis. [Base period is 1961‐1990.]
Figure 3 shows maps of GISS and HadCRUT 1998 and 2005 temperature anomalies relative to base period 1961‐1990 (the base period used by HadCRUT). The temperature anomalies are at a 5 degree‐by‐5 degree resolution for the GISS data to match that in the HadCRUT analysis. In the lower two maps we display the GISS data masked to the same area and resolution as the HadCRUT analysis. The “masked” GISS data let us quantify the extent to which the difference between the GISS and HadCRUT analyses is due to the data interpolation and extrapolation that occurs in the GISS analysis. The GISS analysis assigns a temperature anomaly to many gridboxes that do not contain measurement data, specifically all gridboxes located within 1200 km of one or more stations that do have defined temperature anomalies.
The rationale for this aspect of the GISS analysis is based on the fact that temperature anomaly patterns tend to be large scale. For example, if it is an unusually cold winter in New York, it is probably unusually cold in Philadelphia too. This fact suggests that it may be better to assign a temperature anomaly based on the nearest stations for a gridbox that contains no observing stations, rather than excluding that gridbox from the global analysis. Tests of this assumption are described in our papers referenced below.
Figure 4. Global surface temperature anomalies relative to 1961‐1990 base period for three cases: HadCRUT, GISS, and GISS anomalies limited to the HadCRUT area. [To obtain consistent time series for the HadCRUT and GISS global means, monthly results were averaged over regions with defined temperature anomalies within four latitude zones (90N‐25N, 25N‐Equator, Equator‐25S, 25S‐90S); the global average then weights these zones by the true area of the full zones, and the annual means are based on those monthly global means.]
Figure 4 shows time series of global temperature for the GISS and HadCRUT analyses, as well as for the GISS analysis masked to the HadCRUT data region. This figure reveals that the differences that have developed between the GISS and HadCRUT global temperatures during the past few decades are due primarily to the extension of the GISS analysis into regions that are excluded from the HadCRUT analysis. The GISS and HadCRUT results are similar during this period, when the analyses are limited to exactly the same area. The GISS analysis also finds 1998 as the warmest year, if analysis is limited to the masked area. The question then becomes: how valid are the extrapolations and interpolation in the GISS analysis? If the temperature anomaly scale is adjusted such that the global mean anomaly is zero, the patterns of warm and cool regions have realistic‐looking meteorological patterns, providing qualitative support for the data extensions. However, we would like a quantitative measure of the uncertainty in our estimate of the global temperature anomaly caused by the fact that the spatial distribution of measurements is incomplete. One way to estimate that uncertainty, or possible error, can be obtained via use of the complete time series of global surface temperature data generated by a global climate model that has been demonstrated to have realistic spatial and temporal variability of surface temperature. We can sample this data set at only the locations where measurement stations exist, use this sub‐sample of data to estimate global temperature change with the GISS analysis method, and compare the result with the “perfect” knowledge of global temperature provided by the data at all gridpoints.
| 1880‐1900 | 1900‐1950 | 1960‐2008 | |
|---|---|---|---|
| Meteorological Stations | 0.2 | 0.15 | 0.08 |
| Land‐Ocean Index | 0.08 | 0.05 | 0.05 |
Table 1. Two‐sigma error estimate versus period for meteorological stations and land‐ocean index.
Table 1 shows the derived error due to incomplete coverage of stations. As expected, the error was larger at early dates when station coverage was poorer. Also the error is much larger when data are available only from meteorological stations, without ship or satellite measurements for ocean areas. In recent decades the 2‐sigma uncertainty (95 percent confidence of being within that range, ~2‐3 percent chance of being outside that range in a specific direction) has been about 0.05°C. The incomplete coverage of stations is the primary cause of uncertainty in comparing nearby years, for which the effect of more systematic errors such as urban warming is small.
Additional sources of error become important when comparing temperature anomalies separated by longer periods. The most well‐known source of long‐term error is “urban warming”, human‐made local warming caused by energy use and alterations of the natural environment. Various other errors affecting the estimates of long‐term temperature change are described comprehensively in a large number of papers by Tom Karl and his associates at the NOAA National Climate Data Center. The GISS temperature analysis corrects for urban effects by adjusting the long‐term trends of urban stations to be consistent with the trends at nearby rural stations, with urban locations identified either by population or satellite‐observed night lights. In a paper in preparation we demonstrate that the population and night light approaches yield similar results on global average. The additional error caused by factors other than incomplete spatial coverage is estimated to be of the order of 0.1°C on time scales of several decades to a century, this estimate necessarily being partly subjective. The estimated total uncertainty in global mean temperature anomaly with land and ocean data included thus is similar to the error estimate in the first line of Table 1, i.e., the error due to limited spatial coverage when only meteorological stations are included.
Now let’s consider whether we can specify a rank among the recent global annual temperatures, i.e., which year is warmest, second warmest, etc. Figure 1a shows 2009 as the second warmest year, but it is so close to 1998, 2002, 2003, 2006, and 2007 that we must declare these years as being in a virtual tie as the second warmest year. The maximum difference among these in the GISS analysis is ~0.03°C (2009 being the warmest among those years and 2006 the coolest). This range is approximately equal to our 1‐sigma uncertainty of ~0.025°C, which is the reason for stating that these five years are tied for second warmest.
The year 2005 is 0.061°C warmer than 1998 in our analysis. So how certain are we that 2005 was warmer than 1998? Given the standard deviation of ~0.025°C for the estimated error, we can estimate the probability that 1998 was warmer than 2005 as follows. The chance that 1998 is 0.025°C warmer than our estimated value is about (1 – 0.68)/2 = 0.16. The chance that 2005 is 0.025°C cooler than our estimate is also 0.16. The probability of both of these is ~0.03 (3 percent). Integrating over the tail of the distribution and accounting for the 2005‐1998 temperature difference being 0.61°C alters the estimate in opposite directions. For the moment let us just say that the chance that 1998 is warmer than 2005, given our temperature analysis, is at most no more than about 10 percent. Therefore, we can say with a reasonable degree of confidence that 2005 is the warmest year in the period of instrumental data.
Figure 5. (a) global map of December 2009 anomaly, (b) global map of Jun‐Jul‐Aug 2009 anomaly. #4 and #2 indicate that December 2009 and JJA are the 4th and 2nd warmest globally for those periods.
What about the claim that the Earth’s surface has been cooling over the past decade? That issue can be addressed with a far higher degree of confidence, because the error due to incomplete spatial coverage of measurements becomes much smaller when averaged over several years. The 2‐sigma error in the 5‐year running‐mean temperature anomaly shown in Figure 2, is about a factor of two smaller than the annual mean uncertainty, thus 0.02‐0.03°C. Given that the change of 5‐year‐mean global temperature anomaly is about 0.2°C over the past decade, we can conclude that the world has become warmer over the past decade, not cooler.
Why are some people so readily convinced of a false conclusion, that the world is really experiencing a cooling trend? That gullibility probably has a lot to do with regional short‐term temperature fluctuations, which are an order of magnitude larger than global average annual anomalies. Yet many lay people do understand the distinction between regional short‐term anomalies and global trends. For example, here is comment posted by “frogbandit” at 8:38p.m. 1/6/2010 on City Bright blog:
“I wonder about the people who use cold weather to say that the globe is cooling. It forgets that global warming has a global component and that its a trend, not an everyday thing. I hear people down in the lower 48 say its really cold this winter. That ain’t true so far up here in Alaska. Bethel, Alaska, had a brown Christmas. Here in Anchorage, the temperature today is 31[ºF]. I can’t say based on the fact Anchorage and Bethel are warm so far this winter that we have global warming. That would be a really dumb argument to think my weather pattern is being experienced even in the rest of the United States, much less globally.”
What frogbandit is saying is illustrated by the global map of temperature anomalies in December 2009 (Figure 5a). There were strong negative temperature anomalies at middle latitudes in the Northern Hemisphere, as great as ‐8°C in Siberia, averaged over the month. But the temperature anomaly in the Arctic was as great as +7°C. The cold December perhaps reaffirmed an impression gained by Americans from the unusually cool 2009 summer. There was a large region in the United States and Canada in June‐July‐August with a negative temperature anomaly greater than 1°C, the largest negative anomaly on the planet.
Figure 6. Arctic Oscillation (AO) Index. Positive values of the AO index indicate high low pressure in the polar region and thus a tendency for strong zonal winds that minimize cold air outbreaks to middle latitudes. Blue dots are monthly means and the red curve is the 60‐month (5‐year) running mean.
How do these large regional temperature anomalies stack up against an expectation of, and the reality of, global warming? How unusual are these regional negative fluctuations? Do they have any relationship to global warming? Do they contradict global warming?
It is obvious that in December 2009 there was an unusual exchange of polar and mid‐latitude air in the Northern Hemisphere. Arctic air rushed into both North America and Eurasia, and, of course, it was replaced in the polar region by air from middle latitudes. The degree to which Arctic air penetrates into middle latitudes is related to the Arctic Oscillation (AO) index, which is defined by surface atmospheric pressure patterns and is plotted in Figure 6. When the AO index is positive surface pressure is high low in the polar region. This helps the middle latitude jet stream to blow strongly and consistently from west to east, thus keeping cold Arctic air locked in the polar region. When the AO index is negative there tends to be low high pressure in the polar region, weaker zonal winds, and greater movement of frigid polar air into middle latitudes.
Figure 6 shows that December 2009 was the most extreme negative Arctic Oscillation since the 1970s. Although there were ten cases between the early 1960s and mid 1980s with an AO index more extreme than ‐2.5, there were no such extreme cases since then until last month. It is no wonder that the public has become accustomed to the absence of extreme blasts of cold air.
Figure 7. Temperature anomaly from GISS analysis and AO index from NOAA National Weather Service Climate Prediction Center. United States mean refers to the 48 contiguous states.
Figure 7 shows the AO index with greater temporal resolution for two 5‐year periods. It is obvious that there is a high degree of correlation of the AO index with temperature in the United States, with any possible lag between index and temperature anomaly less than the monthly temporal resolution. Large negative anomalies, when they occur, are usually in a winter month. Note that the January 1977 temperature anomaly, mainly located in the Eastern United States, was considerably stronger than the December 2009 anomaly. [There is nothing magic about a 31 day window that coincides with a calendar month, and it could be misleading. It may be more informative to look at a 30‐day running mean and at the Dec‐Jan‐Feb means for the AO index and temperature anomalies.]
The AO index is not so much an explanation for climate anomaly patterns as it is a simple statement of the situation. However, John (Mike) Wallace and colleagues have been able to use the AO description to aid consideration of how the patterns may change as greenhouse gases increase. A number of papers, by Wallace, David Thompson, and others, as well as by Drew Shindell and others at GISS, have pointed out that increasing carbon dioxide causes the stratosphere to cool, in turn causing on average a stronger jet stream and thus a tendency for a more positive Arctic Oscillation. Overall, Figure 6 shows a tendency in the expected sense. The AO is not the only factor that might alter the frequency of Arctic cold air outbreaks. For example, what is the effect of reduced Arctic sea ice on weather patterns? There is not enough empirical evidence since the rapid ice melt of 2007. We conclude only that December 2009 was a highly anomalous month and that its unusual AO can be described as the “cause” of the extreme December weather.
We do not find a basis for expecting frequent repeat occurrences. On the contrary. Figure 6 does show that month‐to‐month fluctuations of the AO are much larger than its long term trend. But temperature change can be caused by greenhouse gases and global warming independent of Arctic Oscillation dynamical effects.
Figure 8. Global maps 4 season temperature anomalies for ~2009. (Note that Dec is December 2008. Base period is 1951‐1980.)
Figure 9. Global maps 4 season temperature anomaly trends for period 1950‐2009.
So let’s look at recent regional temperature anomalies and temperature trends. Figure 8 shows seasonal temperature anomalies for the past year and Figure 9 shows seasonal temperature change since 1950 based on local linear trends. The temperature scales are identical in Figures 8 and 9. The outstanding characteristic in comparing these two figures is that the magnitude of the 60 year change is similar to the magnitude of seasonal anomalies. What this is telling us is that the climate dice are already strongly loaded. The perceptive person who has been around since the 1950s should be able to notice that seasonal mean temperatures are usually greater than they were in the 1950s, although there are still occasional cold seasons.
The magnitude of monthly temperature anomalies is typically 1.5 to 2 times greater than the magnitude of seasonal anomalies. So it is not yet quite so easy to see global warming if one’s figure of merit is monthly mean temperature. And, of course, daily weather fluctuations are much larger than the impact of the global warming trend. The bottom line is this: there is no global cooling trend. For the time being, until humanity brings its greenhouse gas emissions under control, we can expect each decade to be warmer than the preceding one. Weather fluctuations certainly exceed local temperature changes over the past half century. But the perceptive person should be able to see that climate is warming on decadal time scales.
This information needs to be combined with the conclusion that global warming of 1‐2°C has enormous implications for humanity. But that discussion is beyond the scope of this note.
References:
Hansen, J.E., and S. Lebedeff, 1987: Global trends of measured surface air temperature. J. Geophys. Res., 92, 13345‐13372.
Hansen, J., R. Ruedy, J. Glascoe, and Mki. Sato, 1999: GISS analysis of surface temperature change. J. Geophys. Res., 104, 30997‐31022.
Hansen, J.E., R. Ruedy, Mki. Sato, M. Imhoff, W. Lawrence, D. Easterling, T. Peterson, and T. Karl, 2001: A closer look at United States and global surface temperature change. J. Geophys. Res., 106, 23947‐23963.
Hansen, J., Mki. Sato, R. Ruedy, K. Lo, D.W. Lea, and M. Medina‐Elizade, 2006: Global temperature change. Proc. Natl. Acad. Sci., 103, 14288‐14293.
Sean@543, Uh, no. The climat scientists have been VERY up front that small differences are not significant. Maybe you haven’t met Jim Hansen. He’s a climate scientist. The press is not so circumspect. Records sell papers.
And yes, the facts are clear–you’ve just got them wrong. The warm periods you cite are likely not global, any more than the MWP. And yes, there have been wamer epochs on Earth, but I don’t think the dinosaurs had a complex, global civilization that was trying to support 9 billion individuals–or are you one of those creationist biologists who tries to cram all prehistory into the 2000 years before the FLUD.
The consensus model of Earth’s climate has been tremendously successful. It has the unfortunate implication that our love of fossil fuels is changing the planet’s climate–a prediction first made 114 years ago by Arrhenius. If you don’t like that conclusion, great. Come up with a better model that does not have that implicaton. ‘Til then, we’ll stick with science.
Tim Jones @ 536:
That’s complete and utter nonsense. Whale oil consumption was effectively ended by large scale, =cheaper= crude oil production. Peak oil is going to make crude oil extremely expensive, relative to newer technologies.
In the solar biz we talk about the “Apocalypse” crowd — people who are installing solar power as a way to avoid the Coming Apocalypse when the World Runs Out of Oil. Let’s just say that crowd is growing. As soon as solar goes from that fringe, as well as the Tree Hugger crowd, we’ll see a major change in how people perceive energy costs.
Several years ago I calculated the cost it would take to completely remove “carbon-based energy” from my life. It was right around $75,000 for a 7.5KW DC solar system. That would have provided 100% of my gasoline, natural gas, and coal-fired electricity. That same system today is between $52,500 and $45,000. Taking into account energy savings I’ve done =since= that calculation, the actual cost would be closer to $41,600. At my old rate of energy consumption, payback would be 76 months, or a bit over 6 years, with a system life of 25 years. That 76 month payback doesn’t take into account rising energy costs, so the payback would be even faster. The electricity I make right NOW cost $0.23 / KWh to deploy, with the lowered cost of materials it would be about $0.17 / KWh. I’m paying Green Mountain Energy $0.145 / KWh.
And yes, right now I’m looking into where to site the rest of the solar array and collectors because the add-on cost to get to that size system is about $15,000 with the equipment I own already.
Yes, and it can be produced at prices that will bankrupt the planet far sooner than it is all gone.
Al Gore and the IPCC would have a lot more credibility if they included the economic destruction contained within the FINANCIAL assumptions underlying BAU.
FCH: “Al Gore and the IPCC would have a lot more credibility if they included the economic destruction contained within the FINANCIAL assumptions underlying BAU.”
Given how Al Gore is villified because he’s not a scientist and Stern vilified because he’s an economist when they talk about climate, how do you think it will go when the IPCC start talking about economics, let alone Al Gore?!?
Gilles:
“Ray, actually things have changed since 1970. The energy efficiency has indeed improved. Nuclear energy has been developed.”
Nuclear energy has been developed since the 1950’s, Gilles.
And what’s happened nowadays is that VCs don’t want to put money into building new nuclear powerstations unless their risk is covered.
FCH, don’t ignore coal. There’s enough coal to double CO2 concentration in the atmosphere–and they have a lot of money pulling the strings of those in power. Coal can be produced very cheaply precisely because those in power do not hold them accountable for the damage they cause. I’ve lived in Appalachia. Coal is still king–or at the very least, kingmaker.
Completely Fed Up @ 549:
“Peak Oil” is, BY DEFINITION, the peak in production. Once peak oil is reached (a few years ago …), the global daily output will never exceed that value (from a few years ago …).
RE:549 Completely Fed Up says:
24 January 2010
Giles: “Completely Fed Up : I’m totally aware that peak oil means an increase of price, of course. I’m just saying that the peak of production has never been predicted to occur so early by IEA and EIA”
CFU: “And Peak Oil isn’t “peak production”.”
“Peak oil isn’t peak production.”
“Peak oil is not peak production.”
“When peak oil is past, you haven’t necessarily reached peak production.”
“Peak production and peak oil are not the same.”
Really?
Perhaps you should enter this revelation here:
What is Peak oil?
http://www.peakoil.net/
“The term Peak Oil refers to the maximum rate of the production of oil in any area under consideration, recognising that it is a finite natural resource, subject to depletion.”
Or here:
“Peak oil”
From Wikipedia,
http://en.wikipedia.org/wiki/Peak_oil
“Peak oil is the point in time when the maximum rate of global petroleum extraction is reached, after which the rate of
production enters terminal decline.
“The concept is based on the observed production rates of individual oil wells, and the combined production rate of a field of related oil wells. The aggregate production rate from an oil field over time usually grows exponentially until the rate peaks and then declines—sometimes rapidly—until the field is depleted.
“This concept is derived from the Hubbert curve, and has been shown to be applicable to the sum of a nation’s domestic production rate, and is similarly applied to the global rate of petroleum production.
“Peak oil is often confused with oil depletion; peak oil is the point of maximum production while depletion refers to a period of falling reserves and supply.”
Re: 552 FurryCatHerder says:
24 January 2010
Tim Jones @ 536: “All this is to say, DO NOT count on peak oil or peak coal to end our emissions crisis and thus our greenhouse gas warming problem.”
“That’s complete and utter nonsense. Whale oil consumption was effectively ended by large scale, =cheaper= crude oil production. Peak oil is going to make crude oil extremely expensive, relative to newer technologies.”
I’m not sure how one is supposed to reply to a preface pejorative like “that’s complete and utter nonsense” except to hang it back on you, where it belongs.
Peak oil is not about the price of oil. Its about a physical reality tied to the decline in oil extraction. Price is secondary to production.
Your calculations do not in any way support your disparaging remark. Large scale whaling ended because the world ran out of large whales around the turn of the century, not because the price of whale oil got too high.
Coal is relatively cheap to produce. Large deposits of coal are easy to obtain.
By the way, I’ve done a little more than “calculate” the price of PV. I’ve installed 6 kW of PV of grid tied PV on the roof
as well as built a battery barn for two inverters and 16 large batteries. We turn the electric meter backwards with central air conditioning on. The investment will take some time to turn the financial aspect around. It may wear out first.
The limiting factor on oil is ERoEI. Energy Returned on Energy Invested.
http://netenergy.theoildrum.com/node/4678
http://www.theoildrum.com/node/2899
“The world is consuming more oil than it is producing.” –The Economist, July 14-20 print edition.
http://www.cbc.ca/news/background/oil/supply_demand.html
“World demand for oil is expected to increase by 54 per cent in the first 25 years of the 21st century, according to the Energy Information Agency of the U.S. government. To meet that demand, the world’s oil-producing countries will have to pump out an additional 44 million barrels of oil each and every day by 2025.”
To meet current production, you have to deliberately pump out the oil: costing energy and money.
To increase more, you need to exploit the less efficient to remove sources.
Costing energy and money.
This is even true if you DO manage to increase production RATES.
“Once peak oil is reached (a few years ago …), ”
The problem with that definition, is that if the price of oil goes high enough, you could start exploiting coal reserves and tar shale extraction.
Now you’ve increased production and fossil-fundies proclaim “See!!!! The scientists got it wrong AGAIN!!!”.
Your version is far too fungible, my definition is the economic one, yours and Tims the engineering one.
To expand on the point: “Large scale whaling ended because the world ran out of large whales around the turn of the century, not because the price of whale oil got too high.”
Peak whale oil (and bone) preceded the end of the industry by about 30 years or so.
http://www.theoildrum.com/files/TOD_whales_bardi_fig1.gif
See:
“Crude Oil: how high can it go? (19th century whaling as a model for oil depletion and price volatility)”
http://www.theoildrum.com/node/3960
One can see from the graphs that the price of whale oil (used for lamps) followed the peak in production.
http://www.theoildrum.com/files/TOD_whales_bardi_fig2.gif
“The results are clear: whaling did follow a Hubbert style “bell shaped curve”, approximated in the graphs with a simple Gaussian. Whales did behave like a non renewable resource and some studies say that at the end of the 19th century hunting cycle there remained in the oceans only about 50 females of the main species being hunted: right whales.
“Now, looking at the historical prices, we see an increase in the vicinity of the peak for both whale oil and whale bone. For whale oil we see a spike after the peak…”
[…] (means, snip)
“There were alternative fuels for lamps: animal fat or vegetable oil, a little more expensive and considered as inferior products; but usable. Then, starting in the 1870s, crude oil started to be commonly available as lamp fuel. It probably had an effect in keeping down the price of whale oil. For whale bone, instead, a replacement didn’t really exist except for steel, which was probably much more expensive during the period that we are considering. But stiffeners for ladies’ clothes were hardly something that people couldn’t live without.”
Thus the price of whale oil was kept _lower_ because of crude oil.
Re: 362 Richard Steckis says…
“You bring up the good old ocean acidification crock.”
Oh really? It has been documented (and deeply studied) in the best open, peer-reviewed, juried world-wide scientific journals humanity has, it has been documented for a long time and has held up over time under intense scrutiny unlike the contrarian’s work. A small sampling of published peer reviewed journal articles on ocean PH:
K Caldeira, ME Wickett, Nature, 1995 (cited 373 times)
MR Palmeret al., Science, 1998 (cited 57 times)
A Sanyal, NG Hemming, GN Hanson, WS Broecker 1995, Nature
JC Orr et al., Nature, 2005 (cited 387 times)
K Caldeira, ME Wickett, Nature, 2003 (cited 57 times)
O Hoegh-Guldberg et al., Science, 2007 (cited 57 times)
Kleypas, J.A., R.A. Feely, V.J. Fabry, C. Langdon, C.L. Sabine, and L.L. Robbins, 2006. Impacts of Ocean Acid-ification on Coral Reefs and Other Marine Calcifiers: A Guide for Future Research, report of a workshopheld 18–20 April 2005, St. Petersburg, FL, sponsored by NSF, NOAA, and the U.S. Geological Survey, (cited 95 times)
K Caldeira, ME Wickett, J. Geophys. Res, 2005 (cited 90 times)
VJ Fabry, BA Seibel, RA Feely, … – ICES Journal of Marine Science, 2008 (cited 88 times)
SC Doney et al., Annual Review of Marine science, 2009 (cited 55 times)
SC Doney, ret al., PNAS, 2007 (cited 36 times)
JM Guinotte, VJ Fabry – Annals of the New York Academy of Science, 2008 (cited 34 times)
HL Wood et al., Proc. R. Soc., 2008 (cited 30 times)
KRN Anthony et al., Pnas, 2008 (cited 35 times)
JW Morse, Geochimica et Cosmochimica Acta, 2006 (cited 23 times)
JN Havenhand et al., Current Biology, 2008 (cited 23 times)
M Steinacher, et al., 2009 (cited 57 times)
AJ Spivack, CF You, HJ Smith – 1993- Nature (cited 95 times)
D Lemarchand, et al., Nature, 2000 – nature.com (cited 64 times)
MR Palmer, PN Pearson, SJ Cobb – Science, 1998 (cited 57 times)
DM Anderson, D Archer – Nature, 2002 – Nature (cited 35 times)
M Pagani, et al., Cosmochimica Acta, 2005 (cited 38 times)
JC Orr, et al., – Nature, 2005 (cited 387 times)
B Hoenisch, NG Hemming – Earth and planetary science letters, 2005 (cited 28 times)
PN Pearson, MR Palmer – Nature, 2000 (cited 373 times)
K Caldeira, ME Wickett – J. Geophys. Res, 2005 (cited 90 times)
KC Hester, ET Peltzer, WJ Kirkwood, PG, Geophysical Research, 2008 (cited 17 times)
K Caldeira, GH Rau – Geophysical Research Letters, 2000 (cited 58 times)
SC Althorpe, FÂ FernaÂndez-Alonso, BD Chem, 2001 (cited 94 times)
JT Wootton, CA Pfister, JD PNAS 2008, (cited 16 times)
JP Grotzinger, JF Kasting – The Journal of Geology, 1993 (cited 111 times)
CM Turley, JM Roberts, JM Guinotte – Coral Reefs, 2007 (cited 21 times)
U Riebesell, DA Wolf-Gladrow, V Smetacek – Nature, 1993(cited 239 times)
PG Brewer, et al., Marine Chemistry, 2000 (cited 50 times)
JC Zachos, U Rohl, SA Schellenberg, A Sluijs, DA, Science, 2005 (cited 131 times)
PG Brewer, et al., Journal of Geophysical Research, 1994 (cited 34 times)
PG Brewer et al.,, Journal of Geophysical Research 2003 (cited 44 times)
K Caldeira, JF Kasting – Nature, 1992 (cited 114 times)
CDG Harley, A Randall Hughes, KM, Ecology, 2006 (cited 157 times)
RA Feely, CL Sabine, K Lee, W Berelson, J Kleypas, VJ, Science, 2004 (cited 324 times)
EE Adams, et al., Waste Management, 1998 (cited 37 times)
U Riebesell, KG Schulz, RGJ Bellerby, M Botros, P, Nature, 2007 (cited 66 times)
JA Caulfield, Energy Conversion and 1997 (cited 66 times)
JM Edmond – Deep Sea Research and Oceanographic Abstracts, 1970 (cited 208 times)
K Caldeira – IPCC workshop on carbon capture and storage, 2002 (cited 8 times)
O Hoegh-Guldberg, PJ Mumby, AJ Hooten, RS Steneck, Science, 2007 (cited 247 times)
F Gazeau et al., Geophysical Research Letters, 2007 (cited 71 times)
JC Zachos, MW Wara, S Bohaty, ML Delaney, MR, Science, 2003(cited 115 times)
PN Pearson, MR Palmer – Science, 1999 (cited 85 times)
RGJ Bellerby, et al., Deep-sea research. Part 2, 1995 (cited 15 times)
S Kempe, J Kazmierczak – Bulletin de l’Institut océanographique, 1994 (cited 51 times)
Okay, I’m getting tired and I have barely touched the number of peer-reviewed articles on ocean PH changes and its effects. Get it…there’s quite a bit. Imagine how many more there are on human caused climate change going back to 1824.
Non-science below:
I know a woman oceanographer at NCAR (I’ll give you a hint, she is one of the authors listed in a study above). When at a conference, overwhelming evidence was finally presented that the oceans were becoming less PH, she had to go to the bathroom and throw up because she knew what it meant to the ocean life she had been studying for most of her life.
Yeah, it is hardly a crock.
Talking to a senior peer reviewed publishing scientist about this at NCAR two years ago, he stated that he thought it might even be a more immediate threat than climate change itself to humanity. This is because there is still a time issue involved with human-caused climate change (at least this was the case two years ago). This ocean PH problem is happening fast right now even to the United States and has tremendous implications for destroying a lot of the world’s food supply because many people need reef fish to eat.
472
David B. Benson says:
21 January 2010 at 3:07 PM
“Richard Steckis & others — This paper
Atmospheric CO2 concentrations during ancient greenhouse climates were similar to those predicted for A.D. 2100
http://www.pnas.org/content/107/2/576
suggessts, at a minimum, that we cannot be certain that atmospheric CO2 levels were ever much above 1000 ppm.”
You have got to be joking. I suggest you get you head out of the physics books and into some geology books. It is well established that co2 concentrations exceeded 1000 and even 2000ppm in our ancient atmosphere.
Assertions from one paper does not make it fact.
452
Completely Fed Up says:
21 January 2010 at 11:25 AM
RS should have read more.
From the link he gave:
“The “take-home message, “ says Cohen, is that “we can’t assume that elevated CO2 causes a proportionate decline in calcification of all calcifying organisms.””
But RS wants to take home the message that this
a) causes no decline in calcification in all organisms
b) causes no decline in some organisms (if he can’t get you to swallow a)
Another straw man. I have never implied either a) or b). That is your construct which you are trying to attribute to me.
I never said that were would not be problems with calification in many species. Just that many species have the capacity to adapt.
465
Lynn Vincentnathan says:
21 January 2010 at 1:42 PM
“You sound exactly like my senator in her responses to me — Sen. Kathryn Bailey Hutchison (R, TX)”
Sounds like a very smart woman.
491
Ray Ladbury says:
21 January 2010 at 8:28 PM
“Gilles@484 No raindrop thinks that it is the cause of the flood.”
No raindrop thinks.
505
Barton Paul Levenson says:
22 January 2010 at 5:05 AM
“RS: the solubility of co2 is INVERSELY proportional to temperature. If SSTs in the tropics are increasing then the proportion of co2 dissolved into those waters declines
BPL: This is only true at equilibrium. At present acidity is increasing despite increasing temperatures because partial pressure in the atmosphere is increasing faster.”
Thanks for that answer. It makes far more sense than Ladbury’s ravings about chemical potential.
I still disagree with you though. The partial pressure in the atmosphere would have to increase very significantly for you argument to be valid.
I’d sure like to see some of Steckis’s coworkers join the discussion. I wonder if he’s in the mainstream, wherever it is he works. Do any of _them_ publish?
Richard Steckis, did you read the abstract? There it is said that “Empirical estimates of [CO2]atm during Paleozoic and Mesozoic greenhouse climates are based primarily on the carbon isotope composition of calcium carbonate in fossil soils. We report that greenhouse [CO2]atm have been significantly overestimated because previously assumed soil CO2 concentrations during carbonate formation are too high.”
The fact it’s been published in PNAS suggests that this it at least something to think about. That is to say, this may be an alternative method to verify those high numbers of CO2 (atm) you so easily state are well established. Do you wish there would not be an alyernative systems of measurement? Do you want to monopolize measuring? How does that advance science? Sorry, can’t comment on the methods they have used, since I’ve not read the whole article.
“No raindrop thinks.”
And damn few denialists.
Hey, peak oil combatants, anybody here familiar with the term “adelphophagy?”
Re:564 Richard Steckis says:
24 January 2010
“ I never said that were would not be problems with calification in many species. Just that many species have the capacity to adapt.”
No, but you started saying ocean acidification is a crock.
Being a charitable guy, I’ll accept that you’re learning just like the rest of us. If you are a scientist as you claim, you’ll naturally be absorbing the papers and other literature we’ve posted in reply to your comments and use them to evolve a deepened perspective.
That said, since you’re in for the specific enlightenment more than most of us, as a fisheries biologist sampling the real world in his field of expertise, how about categorizing all forms of sea life as its effected by increasing concentrations of CO2 in the ocean?
You’re a biologist, I’m sure you know the drill. Lets see the two lists and settle this problem.
While you’re getting a handle on effected sea species some AGW proponents have studied the atmospheric aspect to find an acceptable level in the air. Actually, about 350 PPMV is safe enough until proven otherwise.
We must already know how many tons of coal per year were burned to get that number. If 350 PPMV atmosphere works for your best sea water concentration, we can start calculating specific emissions from specific places and
start whittling down the problem.
Steckis #567:
Not true, e.g.:
http://jcbmac.chem.brown.edu/myl/hen/carbondioxideHenry.html
You see that solubility decreases about 3% for every degree of temperature increase. Very typical behaviour.
What we have since pre-industrial is less than one K, but some 40% increase in partial pressure, which translates directly into 40% more CO2 dissolved into surface waters.
40% much greater than 3%, agreed?
The full picture is more complicated. Still, the net CO2 flux is into the ocean, driven precisely by the increasing partial pressure, and not yet measurably counteracted by the temperature effect. Here’s to hoping it stays that way.
I have just done a quick analysis of global temperature trends, CO2 levels, sunspots and volcanic activity using commonly available data bases. My main reason was to see what the numbers said about the recently claimed trend of global cooling rather than global warming. I am happy to send the data base, source and analysis to anyone who wants it if you want to argue with my results.
The results were as follows:
Model 1 continuing linear growth in global temperature
R squared (adjusted)=0.79, Coefficients: CO2 0.0080 (p=0.000); Sunspots 0.0006 (p=0.021); volcanic activity -0.004 (p=0.213); constant -2.7 (p=0.000)
Model 2 plateauing warming
R squared (adjusted)=0.80, Coefficients:(CO2)^2 -0.000068; CO2 0.0551 (p=0.019); Sunspots 0.0005 (p=0.055); volcanic activity -0.006 (p=0.082); constant -10.85 (p=0.000)
This predicts a plateauing of temperature increase at a CO2 level of 405 ppm(vol), with this level predicted for around 2018.
What this means is, based on analysis of the data, a view that global warming is levelling out with respect to CO2 is slightly more favoured than a view that global temperature will continue to increase with increasing CO2. Also, in this model the well documented effect of volcanic activity becomes significant at the 90% level. I was somewhat surprised, as I have been blowing off the “its really cooling people” on the basis of “one swallow doesn’t make a summer”.
Looks to me like we need more data on this one.
cheers
John
[Response: Or physics of course. – gavin]
RS: “Thanks for that answer. It makes far more sense than Ladbury’s ravings about chemical potential”
They’re the same thing.
Read up on “elecromigration” and consider why you’re told not to use different metals when making an electrical connection without consideration of their caompatability.
“I still disagree with you though.”
What a surprise.
“The partial pressure in the atmosphere would have to increase very significantly for you argument to be valid.”
And you worked this out, how? Decide you didn’t like being wrong and therefore thought this a good idea for saying it was wrong?
Where’s your working out, boy?
“I never said that were would not be problems with calification in many species. Just that many species have the capacity to adapt.”
Yeah, just like the Dodo had the capacity to adapt to human predation by… dying out.
Steckis, In equilibrium between two reservoirs, chemical potential potential must be equal in the to reservoirs.
http://en.wikipedia.org/wiki/Chemical_potential
You can also look at in terms of partial pressures.
So, evidently we can add physical chemistry to the long list of subjects on which you are clueless.
Sean: Today’s temperatures are not higher (and may be lower) than temperatures created by natural variation in the Medieval, Roman, or Minoan periods.
BPL: Incorrect.
Bradley, R.S., Hughes, M.K., and H.F. Diaz 2003. “Climate Change in Medieval Time.” Science 302, 404-405.
Dean, J.S. 1994. “The Medieval Warm Period on the Southern Colorado Plateau.” Climatic Change 26, 225-241.
Goosse H., Arzel O., Luterbacher J., Mann M.E., Renssen H., Riedwyl N., Timmermann A., Xoplaki E., Wanner H. 2006. “The Origin of the European ‘Medieval Warm Period’.” Clim. Past, 2, 99–113.
Mann, Michael E. et al. 2009. “Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly.” Science 326, 1256-1260.
Osborn, Timothy J. and Keith R. Briffa 2006. “The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years.” Science 311, 841-844.
RS: The partial pressure in the atmosphere would have to increase very significantly for you argument to be valid.
BPL: Up 38% is “significantly.”
Richard Steckis says “Assertions from one paper does not make it fact.”
Please, everyone, take a moment and savor the delicious irony…
RS: the solubility of co2 is INVERSELY proportional to temperature. If SSTs in the tropics are increasing then the proportion of co2 dissolved into those waters declines
BPL: This is only true at equilibrium. At present acidity is increasing despite increasing temperatures because partial pressure in the atmosphere is increasing faster.”
RS: Thanks for that answer. It makes far more sense than Ladbury’s ravings about chemical potential.
Dude, that is what Ray Ladbury’s answer was trying to tell you. All that you have demonstrated is that you have no clue what chemical potentials are. Original “ravings” quoted below:
“Steckis: “And by the way the solubility of co2 is INVERSELY proportional to temperature.”
Ray L: Actually, it depends on the chemical potential, which is temperature dependent. It also depends on atmospheric concentration, and since temperature is rising rougly linearly, while CO2 is rising exponentially…”
Mother nature is still far more powerful than what man has ever done.
By all means let’s reduced GHG emissions gradually, for that is all we can really d at this point anyways, but some of the high end predictions prove to be false while the medium estimates need more evidenc that only time will provide. Steam boilers from the 1800’s had an efficiency of 90-95% and steam can heat large buildings with few to no moving parts… the technology does exist; planting wind mills and solar panels helps but will not solve the issue. Then again we do have more time than Hansen had predicted… this much is pretty clear, so now what do we do with this time?
This paper includes a citation to “many confidential oil- and gas exploration studies” — a reminder that research done not for publication but for confidential business planning can contribute to other science.
Climatologists might consider how to protect the ability to use this material for policy work.
The paper (stumbled on it) is interesting as new information coming out of the Arctic, new proxy information, and new correlations (and has anyone looked at Azolla sp. to see if the rate of growth is changing now?):
http://www3.bio.uu.nl/palaeo/people/Andy/andypdf/Speelman%20et%20al.%202009%20Geobiology.pdf
Geobiology (2009), 7, 155–170,
DOI: 10.1111/j.1472-4669.2009.00195.x
The Eocene Arctic Azolla bloom: environmental conditions,
productivity and carbon drawdown
… The sustained growth of Azolla, currently ranking among the fastest growing plants on Earth, in a major anoxic oceanic basin may have contributed to decreasing atmospheric pCO2 levels via burial of Azolla-derived organic matter. The consequences of these enormous Azolla blooms for regional and global nutrient and carbon cycles are still largely unknown. Cultivation experiments have been set up to investigate the influence of elevated pCO2 on Azolla growth, showing a marked increase in Azolla productivity under elevated (760 and 1910 ppm) pCO2 conditions….
…
… storing 0.9 1018 to 3.5 1018 g carbon would result in a 55 to 470 ppm drawdown of pCO2 under Eocene conditions, indicating that the Arctic Azolla blooms may have had a significant effect on global atmospheric pCO2 levels through enhanced burial of organic matter….
… . Sporadically, mass abundances of Azolla remains have previously been recognized in the Eocene Arctic and Nordic Seas (e.g. Manum et al., 1989; many confidential oil- and gas exploration studies; Eldrett et al., 2004). Yet, concentrations of Azolla megaspores recovered at the Lomonosov Ridge Site are an order of magnitude higher than those found elsewhere (Brinkhuis et al., 2006). Sustained growth of Azolla throughout the Arctic provides important constraints on the Eocene Arctic environment. The presence of the freshwater fern Azolla, both within the Arctic Basin and in all Nordic seas suggests that at least the surface waters were frequently fresh or brackish during the Azolla interval (Brinkhuis et al., 2006). The occurrence of such a fresh surface layer in combination with
…
… Interestingly, the Azolla phase approximately coincided with the onset of a global shift towards heavier deep sea benthic foraminifera δ13C values (Zachos et al., 2001) and an overall global cooling trend. In effect, around this time (~48.5 Ma) the transition from a global greenhouse climate towards the modern icehouse started (Tripati et al., 2005; Zachos et al., 2008), possibly heralded by decreasing atmospheric CO2 concentrations (Pearson & Palmer, 2000; Pagani et al., 2005). Together these notions suggest that sustained growth of Azolla in a major anoxic oceanic basin may have contributed substantially to decreasing atmospheric pCO2-levels…..
Oops, permanent URL for Geobiology (2009), 7, 155–170
DOI: 10.1111/j.1472-4669.2009.00195.x
The Eocene Arctic Azolla bloom: environmental conditions,
productivity and carbon drawdown
is: http://hdl.handle.net/2027.42/62273
I graduated from this space some time ago, but I expect some of you to remember me.
What do I mean, “Graduate?”
I mean there was nothing more to learn.
The sides have become hardened, even as the science and the conditions go on. I do notice that far fewer “regular” people care than ever before; even a year ago, the warming of 2009 would have been big news, dominating in some circles for days or weeks. I notice that the general press barely acknowledged it, and it was gone in a day.
I notice that we still fight over basics. Why? Call it sport, I guess. I notice that “those in the right” have become more and more defensive. Tired of losing to the “wrong” side? I get it.
But the ocean acidification issue, now really. Isn’t this basic chemistry? Let’s see, and I won’t be the one to plug in the numbers, but surely there is an expression here somewhere:
Man has emitted A tons of carbon since 1985.
B is the amount of that carbon which is still in the atmosphere.
C is the amount of that carbon absorbed by the world ocean.
(B and C are derived from samples.)
D represents the liquid volume of the upper layer of the world ocean.
E represents the pH balance of the ocean in 1985.
In the past 25 years, C has been added to D. Some of it has escaped, for which we can allow an error bar, which we need anyway for these estimates.
Now, somebody more skilled than me: Can’t we “prove” what should happen to the pH balance of the world ocean based on these changes?
John Storer@574, Your statistical analysis is invalid. By introducing a slope change, you have more than doubled the number of parameters in your fit. Of course it will give a better fit!
The problem is that there is more to such an analysis than goodness of fit. There is also parsimony of the statistical model. Try a parameter such as AIC or BIC, and you will find that the simpler model still has the greater predictive power. And that is what science is about, after all.
Walt Bennett: no. There is some carbinic acid formation and heating of surface waters but large amounts of heat transfer can go to far deeper depths, and with so much water there is comparaitively little carbonic acid formation (though of concern) and to make matters more complicated the extra aicidity supports certain species of bacteria an algae which intakes excess C02 not to mention methanophiles. The readings of the ocean surfaces do change and are not static. Factor in the hight heat capacity of water as well along with other factors and we still have a lot more to learn at this time.
~carbonic~
I’m no more skilled than Walt but a couple of notes:
— Walt is asking for a global average number, but organisms live in local concentrations– a big difference.
To simplify searching for anyone not clear on how to find this stuff:
http://scholar.google.com/scholar?hl=en&q=ocean+ph&lr=lang_en&as_sdt=2001&as_ylo=2006&as_vis=1
http://www.pnas.org/content/105/48/18848.abstract
“… pH decline is proceeding at a more rapid rate than previously predicted in some areas, and that this decline has ecological consequences for near shore benthic ecosystems.”
Chart and references here:
http://www.www.eoearth.org/article/Ocean_acidification
“… The values shown in the table are global values for ocean surface waters. Changes will be much more pronounced in areas such as the Southern Ocean, which will become undersaturated with respect to aragonite in 2050. Data collected at several time-series stations fully validate the above changes in the carbonate chemistry derived from thermodynamic calculations.”
“I notice that we still fight over basics. Why? Call it sport, I guess.”
Nope.
Zombies.
Or vampires (the nasty neck-sucking ones, not the cool looking ones).
We fight over basics because there still come people debunking the basics with zombie arguments.
What YOU continue to argue the basics over is your look-out walt.
“582
Jacob Mack says:
25 January 2010 at 1:31 PM
Mother nature is still far more powerful than what man has ever done.”
And mother nature will be the cause of the warming because that’s what she does when more CO2 gets emitted.
It isn’t a heat-ray from the humans causing global warming, Jacob, so stop with the strawmen.
> Steam boilers from the 1800’s had an efficiency of 90-95%
Citation needed; I looked and didn’t find anything. Did find:
http://www.facebook.com/topic.php?uid=92495876938&topic=10659
“… condensing boilers with touted efficiencies of 90-95%”
Steckis, unfortunately, has demonstrated no capacity for learning.
Steckis has a BS, no more. He likes to describe himself as a “scientist” so folks who haven’t run across him in the past think he’s at the same level as PhDs doing research in climate science, in other words, an authority.
Walt,
http://www.nsf.gov/pubs/2010/nsf10530/nsf10530.htm?WT.mc_id=USNSF_179
More funding for research on this matter.
> Schwartz
http://julesandjames.blogspot.com/2010/01/more-schwartz.html
“… The calculations presented are rather trivial zero-dimensional energy balance estimates. …
….
There is no useful uncertainty analysis …. despite the misleading title which has predictably resulted in an equally misleading press release and coverage, there is really nothing for anyone (not even the sceptics!) to get excited about.”
Richard Steckis (563) — Actually, I have been an amateur student of geology for over 50 years. In even that interval textbook geology had to be revised; most notibly because of the discovery of plate tectonics.
The paper in question raises serious doubts about at least one of the proxies used to estimate paleoclimate CO2 concentrations. The work was considered good enough to be accepted for publication in PNAS. I suggest you take it rather seriously.
LOL Ray Ladbury.
John Storer,
Try doing partial-F tests on your added variables. I’m especially dubious about the CO2^2 term, since there’s no physical justification for it.
Mr. Hansen, did you leave out a few data points?
http://www.vancouversun.com/technology/Scientists+using+selective+temperature+data+skeptics/2468634/story.html
[Response: No. – gavin]
Thanks for all your comments! This discussion is becoming really interesting , probably more interesting than many of you realize [ see posts 501, 507, 509 including Gavins comment, 511, 512, 514, 520, 522, 523, 527, 539, 540]. But first, let me show you the graph of the GISS (GISTEMP) and MSU RSS (satellite) monthly data in the years 2000 – 2009 (don’t worry about the short time interval – I’ll get back to that in a short moment), you find it at http://jorsater.se/klimatet/MSU%20RSS%20and%20GISS%202000-2009.jpg As you can see, both the GISS data and the satellite data agree reasonably well but they also show discrepancies. You find the linear regression line for both data sets – it is rising but rather slowly, 1,1 C per century for the GISS data and quite a bit less for the MSU RSS (satellite) data. I chose the even year 2000 in order not be accused for cherry picking – if you start at 2001 the GISS data is absolutely flat and the MSU RSS data is actually showing cooling, see http://jorsater.se/klimatet/MSU%20RSS%20and%20GISS%202001-2009.jpg. This is the basis for the claim that global warming has stopped. Everybody with me so far? Good! Now to the statistical significance of such a short time interval. Several of the listed comments above are basic lessons on how long a significant interval should be. Ray Ladbury [post 527] also answered my question as to how long such an interval should be that he would believe in – he says “after 15 years enticing, but it is not definitive”. OK, fine. The only problem is, of course, that if you are looking for a trend change you must look at a reasonably short interval, mustn’t we? Because trend changes is what we are interested in if we want to know if global warming is still going on, isn’t? If we already know it is going on we don’t even need bother looking. Unfortunately, some of you may indeed be right that ten years is too short for us to be able to say anything. Let’s see what an authority says – fortunately Jim Hansen discusses exactly this in another article – the very recent (January 21) report from GISS http://www.giss.nasa.gov/research/news/20100121/
In this article, Hansen says “But when we average temperature over five or ten years to minimize that variability, we find that global warming is continuing unabated.” This statement is very interesting. For one thing, Hansen thinks that something like 5-10 years is enough. So the flat curve in the last nine years ought to start getting interesting! But secondly, Hansen claims that “global warming is continuing unabated”. From what thin air did he get that conclusion? The recent curves are quite flat, as we just saw! We know that the world got warmer from 1900-2000 – that he demonstrates clearly in the graphs in the paper (which is misleading since the last decade – which is the real subject, is hardly visible) we are commenting. But how do we know that warming is going on now? From what many of you have been writing – no measurements can tell us whether it is going on now or, for that matter in the last ten years. How is it then possible that the NASA report claims that “global warming is going on unabated”!? The fact the we just had the warmest decade doesn’t tell us anything (and the second warmest year stuff even less). Or does it? We have to make up our mind – if a clear flat trend is not significant then a hypothesised rising one isn’t either! What’s more – the NASA report is released as news which gives the false impression that measurements have verified recent global warming. This NASA text is sent to journalists of which many most certainly do not how to it should be interpreted.
Hansen should of course have written : The last year was the warmest on record and so was the last decade but the time period is really too short to tell us anything about global warming! It could still be going on and it could have stopped or been reversed – we cannot really tell. Please do not come to any false conclusions! In the paper we comment here Hansen and coworkers are more cautious – they essentially only states that no cooling is going on (again – how does he know what lurks behind the noise!)
But there is more to our discussion here. When I wrote about the satellite data I got comments from Ray Ladbury [512 and 522] that they are hard to calibrate. That may be so but this is a very strange argument as to why they should be left out in Hansen’s et al. paper. Is the moral – any data contradicting your results are left out and should anyone discover that, you do your best to discredit that data?! Not very scientific! Hanssen should of course have commented on the satellite data and possible discrepancies and, if he thought them inferior, clearly have stated that and also given appropriate references.
Finally, let’s get back to the models which several of you comment upon. Climate models are fine science, don’t get me wrong on that. They are the best we can do. But it is their uncritical application to the real world that I am worried about. Several of you claim that they are well tested. That confuses me. To my knowledge the conventional wisdom is that the earth hasn’t had the present abundance of carbon dioxide in several millions of years (and proxy data is poor over such time) and certainly far longer back in time for the levels projected for the future by the IPCC. How could you then have tested the models with high levels of carbon dioxide AND compared them with detailed real measurements?
Finally, it should be stressed that the models CAN be reasonably tested for low CO2 situations. Run them backwards and reproduce the entire past century, the Little Ice Age and the Medieval Warm Period and the general picture of the last ice age and I shall be a believer. This has not been done, as far as I know. It requires, of course, abstaining from fine tuning such as fiddling with aerosols – if you allow such things you can fit anything. Also I should mention that there might be a semantic problem. Climate models is one thing but to really know what is happening with the climate over long time you need to model the entire earth system including the biosphere. Are you really saying that all this is well understood?
Finally, a comment to Ray Ladbury [527]. I don’t think rude language has ever been effective as a tool for convincing people in a scientific discussion. Frankly, it has quite the opposite effect.