The countries of the G8 today approved a target of 2° C rise in global average temperature above the natural, preanthropogenic climate, that they resolve should be avoided. The Europeans have been pushing for 2 degrees as a target maximum temperature for several years, but this is something of a development for the Americans. We posted recently on two new papers about what it would take to limit global average warming, finding that it would require fairly strong change in trajectory. About 2° C as a target, we wrote,
… even a “moderate” warming of 2°C stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations. Global warming of 2°C would leave the Earth warmer than it has been in millions of years, a disruption of climate conditions that have been stable for longer than the history of human agriculture. Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8°C of warming so far, a target of 2°C seems almost cavalier.
Nevertheless, we view today’s development as a constructive step.
quick update –
from what I’ve been reading, environmental impacts and energy payback times (EPBT) will be different from different reports at least in part due to the state of the technology. Improvements in PV technology, quality and manufacturing efficiency (from learning and mass market advantages) will make more recent values significantly better.
I found one source given nuclear and wind low CO2 per kWh (from memory, nuclear around 20 g (or 10?) CO2 or CO2-equivalent per kWh), while solar PV was listed as being a couple to several times greater in CO2 emissions per unit energy. However, even then, it was much better than fossil fuels.
(PS there are also emissions and energy consumption associated with fossil fuel energy supply outside the combustion of fuel, since power plants have to be built and run, etc.).
But other sources give solar PV CO2(-eq) emissions being more similar to nuclear emissions (20 to 30 g/kWh). (and EPBTs from under 1 year to ~4 years, depending on location and technology…) Although other sources put nuclear CO2 equivalent emissions as being even lower again (8 g /kWh).
The general assumption for solar PV is a lifetime of 30 years. Doubling that and adding some extra time (to make up for performance decay) could cut EPBT and emissions by almost half (most emissions and energy inputs are not from operation and maintenance – this may be less true of nuclear power).
Of course, the energy mix used also matters – emissions vary depending on where the solar modules are made, perhaps also where nuclear fuel is mined, how far oil and coal must be transported, etc. And this will change over time – CO2 emissions should keep getting lower just from reducing fossil fuel usage in proportion to total energy use.
Interestingly, while in normal operation at least, nuclear power emits less radioactivity than coal power plants, it is also true that during at least normal operations, solar power emits less cadmium than coal power plants – and the least emissions (among the technologies studied, so far as I know) of Cd are from CdTe solar cells!
more coming… (please keep open for comments)
An update to the “Solar Grand Plan”
http://www.clca.columbia.edu/papers/sun&wind-1.pdf
sheesh 2 DEGREES just look at the s**t we are getting at 0.8 degrees Its like goodbye coral reefs,goodbye amazon rainforest,goodbye himalayan glaciers that provide water to 40% worlds population (lot of poeple in china),goodbye east india monsoon rains needed to grow crops,hello more droughts,hello more forest fires,hello more heat waves, hello more stronger huricanes/typhones/cyclones,hello more floods (because warmer oceans have even more water evaporated from them turned into clouds and blown over land so even more rain pours down at once),hello more jellyfish(they thrive in acidified oceans because of CO2 absorbtion).Volcanoes and Earthquakes caused by rock breaking along fault lines I think should stay the same because they are powered by processes within the earth and not within the oceans or atmosphere.
I hope this don’t turn out like the New Orleans levay The sientists warned people to fix it or when a certin catergory huricane came along it whould break and the water in the city would rise to a certin level.But probly because it reqiered finacial sacrifice the levey was never fixed.The scientists even said in a documentary that New Orleans was a disaster in the waiting.Then sometime later Katrina came along and just as the scientists said the levay broke and just as the scientists said water rose to a certin level in the city.Now is New Orleans better off financialy for not sacrifising some money to fix the levay?
How about smoking tobacco, scientists warned poeple about it causing lung cancer but probly not much poeple listened to them until alot of poeple died from lung cancer.
Must we only change our ways because of suffering?
Arn’t we inteligent enough to change before we suffer?
“Arn’t we inteligent enough to change before we suffer?
Comment by Sara”
with 6 million people, you’ll find thousands or millions willing to say there is no problem.
And given that AGW requires the rich first world pay *now* for the sake of the poor third world in the future (and the rich first world in a few generations, but they aren’t even BORN yet!), there’s plenty of desire to ignore a problem.
Show me studies of people who stopped drinking at 20 to save the liver of an old man at 60. Even when it is themselves, they don’t care, it’s 40 years away…
6 billion, of course…
Sory about putting a word in the above post it’s just that Im so frustrated that it seems like countries are going to not do what the scientists need them to do to have a good chance to avoid catastrophy because of money. I hope history dosnt repeat itself with this one. Because if it dose we might be stuck down the rabit whole for good because of runaway global warming caused by more bushfires and more melting of the permafrost releasing greenhouse gases and establishing a positive feedback loop.
“it seems like countries are going to not do what the scientists need them to do to have a good chance to avoid catastrophy ”
“What the scientists see as the need to do” is more accurate. I was only joking about the world-domination-as-a-hobby.
A bit like being the only breadwinner in a poor but large family. Your doctor says you are going to die within three years if you don’t change your diet, exercise a little and give up smoking.
But because you don’t want to be told what to do by “some egghead” and exercising costs money (and ignoring that giving up smokes saves more money), you deny there’s a problem.
In three years your family will be thrown out of their rented apartment because you died and they will live on the streets. Sure, they may survive, but their lives will be much poorer, even if you discount the fact you no longer are with them.
And you wonder why, before then and after the advice and refusing it, your family and friends are angry with your decision.
The denialists who make no money out of fossil fuels are that man.
Hi everyone.
I have been reading the dicussions on this site for a while now but this is my first post. Congratulations on an excellent discussion on the realities of Global Warming.
I have a number of questions/comments that I would like to put out for clarification or response:
My first one is this:
Regarding the 2C warming target that is much discussed as being needed to avoid ‘dangerous warming’. Leaving aside the merits or otherwise of that as a particular target, I have some confusion regarding where the world stands wrt to it right now. One statement put about is the AGW to date is around 0.8C, with another 0.6C ‘locked in’ as we wait for lags in the system to catch up – presumably primarily the themal lag as we wait for the oceans to warm. Then there is stated to be another 0.5C warming being masked by aerosol pollution, principally in Asia that will clear as they hopefully clean up their air. So basically we are already at 2C in effect, just waiting for it to happen. And all this at 390 ppm CO2. I presume this is the basis for recent statements that our target for stabilisation needs to be 360 ppm or even lower.
On the other hand we have the worlds leaders slowly moving towards a target of 2C AGW based on various levels of emmissions restraint that are -50% to -80% emmissions reductions by 2050 type of figures, resulting in perhaps as much cumulative emmissions by 2050 as we have had since the start of the Industrial Revolution.
How can we be seemingly be at our 2C limit now, although it is masked, when the policy direction (lets leave aside the politics, economics, engineering etc of whether it can actually be delivered) seems to be saying that we can pump out a lot more and still hit the target. Am I missing something basic here? Is there serious disagreement within the Scientific community about what is needed to achieve a 2C limit. Is the politics working on outdated science? Is the politics just politics. And how good is the scientific consensus on targets and where we are now?
Am I missing something because this looks like 2 + 2 = 8.
“How can we be seemingly be at our 2C limit now, although it is masked,”
One is that some of the CO2 out there will go away if we reduce NOW. That may undo some of the warming already done and likewise reduce the amount in the pipeline (since it will reduce before it appears).
It’s one reason why the targets being “by 2050” is pants: if we wait till 2045 and do it all in 5 years, we will see all the warming in the pipeline and THEN some 50 years later (figure pulled from thin air) see the reduction.
The politicians have seen “if we reduce by 2050” and signed up to that without thinking about how that shows up if they do it all now, evenly over the next 40 years or right at the last minute.
But there’s not a lot of political points in doing the hard stuff now, so they prevaricate.
Re 410 Mark – “The politicians have seen “if we reduce by 2050″ and signed up to that without thinking about how that shows up if they do it all now, evenly over the next 40 years or right at the last minute.”
Maybe, and a good point to bear in mind, but the possibilities are constrained by economic inertia – I’d expect the change to be distributed over time (except when anthropogenic net emissions do approach zero – then there might be a slam into the zero line, and if there is not much sequestration, it would stop changing around that time).