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A clearer picture how climate change affects El Niño?

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I still remember the first time I was asked about how climate change affects El Niño. It was given as a group exercise during a winter school in Les Houghes (in France) back in February 1996. Since then, I have kept thinking about this question, and I have not been the only one wondering about this. Now I had my hopes up as a new study was just published on the evolution and forcing mechanisms of El Niño over the past 21,000 years (Liu et al., 2014).

[Read more…] about A clearer picture how climate change affects El Niño?

References

  1. Z. Liu, Z. Lu, X. Wen, B.L. Otto-Bliesner, A. Timmermann, and K.M. Cobb, "Evolution and forcing mechanisms of El Niño over the past 21,000 years", Nature, vol. 515, pp. 550-553, 2014. http://dx.doi.org/10.1038/nature13963

Unforced variations: Nov 2014

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This month’s open thread. In honour of today’s New York Marathon, we are expecting the fastest of you to read and digest the final IPCC Synthesis report in sub-3 hours. For those who didn’t keep up with the IPCC training regime, the Summary for Policy Makers provides a more accessible target.

Also in the news, follow #ArcticCircle2014 for some great info on the Arctic Circle meeting in Iceland.

How do trees change the climate?

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Translations: (Deutsch) (English)

Guest commentary from Abby Swann (U. Washington)

This past month, an op-ed by Nadine Unger appeared in the New York Times with the headline “To save the climate, don’t plant trees”.  The author’s main argument is that UN programs to address climate change by planting trees or preserving existing forests are “high risk” and a “bad bet”. [Ed. There is more background on the op-ed here]

However, I don’t think that these conclusions are supported by the science.  The author connects unrelated issues about trees, conflates what we know about trees from different latitudes, and fails to convey the main point: tropical trees keep climate cool locally, help keep rainfall rates high, and have innumerable non-climate benefits including maintaining habitat and supporting biodiversity.

[Read more…] about How do trees change the climate?

Ocean heat storage: a particularly lousy policy target + Update

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The New York Times, 12 December 2027: After 12 years of debate and negotiation, kicked off in Paris in 2015, world leaders have finally agreed to ditch the goal of limiting global warming to below 2 °C. Instead, they have agreed to the new goal of limiting global ocean heat content to 1024 Joules. The decision was widely welcomed by the science and policy communities as a great step forward. “In the past, the 2 °C goal has allowed some governments to pretend that they are taking serious action to mitigate global warming, when in reality they have achieved almost nothing. I’m sure that this can’t happen again with the new 1024 Joules goal”, said David Victor, a professor of international relations who originally proposed this change back in 2014. And an unnamed senior EU negotiator commented: “Perhaps I shouldn’t say this, but some heads of state had trouble understanding the implications of the 2 °C target; sometimes they even accidentally talked of limiting global warming to 2%. I’m glad that we now have those 1024 Joules which are much easier to grasp for policy makers and the public.”

This fictitious newspaper item is of course absurd and will never become reality, because ocean heat content is unsuited as a climate policy target. Here are three main reasons why. [Read more…] about Ocean heat storage: a particularly lousy policy target + Update

New developments: Climate services for health

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I recently received a joint email from the World Meteorological and Health organisations (WMO & WHO) which I like to bring to the attention of our readers. Both because it shows the direction of some new developments, but also because the WMO and WHO are inviting people to share their experience with health and climate. We wrote a post on the subject climate and health in 2011, based on a book by Paul Epstein (who sadly pased away in November 2011) and Dan Ferber (Health on a Changing Planet), and are glad to see an increased emphasis on this topic. The call from WMO/WHO goes as follows:

Guest commentary from Joy Shumake-Guillemot

CALL FOR CASE STUDIES
Climate Services for Health
Enhancing Decision Support for Climate Risk Management and Adaptation

Climate services for health are an emerging technical field for both the health and climate communities. In 2012, WHO and WMO jointly published the Atlas on Climate and Health, drawing attention to the key linkages between climate and health, and how climate information can be used to understand and manage climate sensitive health risks. A new follow-up publication of Case Studies on Climate Services for Health is in preparation, and will take a next step to outline with greater detail how a wide range of health applications can benefit from using climate and weather information; what steps and processes can be used to co-develop and use climate and weather information in the health sector; and showcase how such partnerships and services can really make a difference to the health community. 

Submission Guidance – Deadline October 31, 2014
We invite you to share your experiences and call attention to the increasing opportunities to solve health problems with climate service solutions. Case studies should highlight existing partnerships and good practices that demonstrate the broad range of possible applications and the value of using climate information to inform health decisions. Case studies from across health science and practice are welcomed, including examples of climate services for integrated surveillance, disease forecasting, early warning systems, risk mapping, health service planning, risk communication, research, evaluation, infrastructure siting, etc. Additionally, the publication aims to highlight the full range climate-related health issues and risks (i.e. nutrition, NCDs, air pollution, allergens, infectious diseases, water and sanitation, extreme temperatures and weather, etc.) where health decision-making can benefit from climate and weather knowledge at historic, immediate, seasonal, or long-term time scales.

Case studies should be short (~600 words, 2 pages incl. images/diagrams and references) and designed to highlight the added-value that climate services have made for managing climate risks to health. Please find additional guidance on the structure and four elements to be included at http://www.gfcs-climate.org/node/579.  

For questions and submission please contact
Dr.Joy Shumake-Guillemot jshumake-guillemot@wmo.int
WHO/WMO Climate and Health Office, World Meteorological Organization, Geneva, Switzerland

Climate response estimates from Lewis & Curry

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Guest commentary from Richard Millar (U. Oxford)

The recent Lewis and Curry study of climate sensitivity estimated from the transient surface temperature record is being lauded as something of a game-changer – but how much of a game-changer is it really?

[Read more…] about Climate response estimates from Lewis & Curry

References

  1. N. Lewis, and J.A. Curry, "The implications for climate sensitivity of AR5 forcing and heat uptake estimates", Climate Dynamics, vol. 45, pp. 1009-1023, 2014. http://dx.doi.org/10.1007/s00382-014-2342-y

Limiting global warming to 2 °C – why Victor and Kennel are wrong + update

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In a comment in Nature titled Ditch the 2 °C warming goal, political scientist David Victor and retired astrophysicist Charles Kennel advocate just that. But their arguments don’t hold water.

It is clear that the opinion article by Victor & Kennel is meant to be provocative. But even when making allowances for that, the arguments which they present are ill-informed and simply not supported by the facts. The case for limiting global warming to at most 2°C above preindustrial temperatures remains very strong.

Let’s start with an argument that they apparently consider especially important, given that they devote a whole section and a graph to it. They claim:

The scientific basis for the 2 °C goal is tenuous. The planet’s average temperature has barely risen in the past 16 years. [Read more…] about Limiting global warming to 2 °C – why Victor and Kennel are wrong + update

Free climate science / modeling class beginning Sept. 29

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Global Warming: The Science and Modeling of Climate Change is a free online adaptation of a college-level class for non-science majors at the University of Chicago (textbook, video lectures). The class includes 33 short exercises for playing with on-line models, 5 “number-cruncher” problems where you create simple models from scratch in a spreadsheet or programming language, and 8 “explainer” assignments where you explain some concept as you would to a smart 11-year old child (short, simple, clear), and exchange these with other students in the class for feedback. The discussion forums are very lively, as thousands of people from around the world make their way through the video lectures and exercises, lots to chat about. This is our third run of the class, so we’re getting the kinks out. We hope you find it useful. September 29 – December 31 2014.

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