Climate science - Feb 5
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You're Getting Warmer
Andrew Dessler, Gristmill
...My overall first impression was pleasant surprise at the strong wording in the document. Assessments, like the science that underlies them, tend to be conservative, so strong statements are often couched in so many caveats that they come out with the consistency of soggy toast. The statements in the AR4 SPM are crisp and clear and tough, reflecting the fact that our knowledge of the climate system is now so good that few caveats are necessary.
Here are some important new results from today's summary:
Over the past five years, there have been virtually no breakthrough findings that revolutionized the science of climate change. There have been some tremendous scientific results, but they have largely confirmed and refined what we already thought we knew: the climate is warming, humans are playing a role, and we can expect further warming of a few degrees if we don't reduce our emissions of greenhouse gases.
The stability of the dominant climate-science paradigm should be both reassuring and unsettling: reassuring because it suggests we understand the climate pretty well; unsettling because it forecasts potentially serious impacts if we don't take action soon. There's a tremendous amount of information in the AR4 SPM. Read the report for yourself [PDF] --- and then write your representatives in Congress.
Andrew Dessler is an associate professor in the Department of Atmospheric Sciences at Texas A&M University; his research focuses on the physics of climate change, climate feedbacks in particular. He blogs at Gristmill.
(5 Feb 2007)
Readable summary of the IPCC report from a climate scientist. -BA
A Disaster Epic (in Slo-Mo)
Andrew C. Revkin, NY Times
The fourth report since 1990 from the Intergovernmental Panel on Climate Change, a huge network of climate experts operating under the United Nations, contained much to fear, but no clanging alarm bells were attached.
...As it turned out, the panel’s scientific projections deflated some of the more dramatic possibilities.
The report includes the biblical risk of the world’s seas rising - everywhere - a dozen feet or more. Such a view renders a highly charged recent debate over whether seas would rise a few inches or a few feet in this century “lampoonable,” in the words of Jerry Mahlman, a veteran climate expert.
But the panel’s prognosis for sea level, while epic, is dispersed over dizzying stretches of time: a thousand years or more.
In essence, the debate over characterizing the near-term rise in seas is akin to arguing whether a car starting to roll down a hill toward a cliff is going 1 mile per hour or 2.
(4 Feb 2007)
The human hand in climate change
Kerry Emanuel, Boston Review
...This basic climate physics is entirely uncontroversial among scientists. And if one could change the concentration of a single greenhouse gas while holding the rest of the system (except its temperature) fixed, it would be simple to calculate the corresponding change in surface temperature. For example, doubling the concentration of CO2 would raise the average surface temperature by about 1.4°F, enough to detect but probably not enough to cause serious problems. Almost all the controversy arises from the fact that in reality, changing any single greenhouse gas will indirectly cause other components of the system to change as well, thus yielding additional changes. These knock-on effects are known as feedbacks, and the most important and uncertain of these involves water.
...On the bright side, the governments of many countries, including the United States, continue to fund active programs of climate research, and many of the critical uncertainties about climate change are slowly being whittled down. The extremists are being exposed and relegated to the sidelines, and when the media stop amplifying their views, their political counterparts will have nothing left to stand on. When this happens, we can get down to the serious business of tackling the most complex and perhaps the most consequential problem ever confronted by mankind.
Like it or not, we have been handed Phaeton’s reins, and we will have to learn how to control climate if we are to avoid his fate.
Kerry Emanuel is a professor of meteorology at MIT and the author of Divine Wind: The History and Science of Hurricanes. In 2006 Time magazine recognized him as one of the world’s 100 most influential people.
Long, readable essay on the science of global warming. -BA
UPDATE: David Roberts of Gristmill writes:
...the first 90% or so is fantastic. This is the kind of piece I'd give someone still doubtful about the basic IPCC consensus -- it's sober and calm, it doesn't overstate the confidence of the science or elide the uncertainties, nor does it cushion the basic conclusion, and it is written with obvious authority and command of the subject matter.
Sadly, it goes off the rails toward the end, when Emanuel wades into political waters and, out of nowhere, pulls a reverse armstand back double somersault False Equivalence maneuver. I give it points for degree of difficulty, but must disqualify it on the basis of accuracy.
( More )
Global-Warming Report Gets U.S. Emphasis
John J. Fialka, Wall Street Journal
WASHINGTON -- U.S. government scientists Friday said the long-term outlook for global warming may be more dire than suggested by this week's United Nations' report, which they say doesn't fully address the impact of clouds and melting glaciers.
Recent evidence of accelerated melting of glaciers in Greenland and the Antarctic ice cap came too late to be included in the report released Thursday by the U.N.-sponsored Intergovernmental Panel on Climate Change.
Glaciers are among the largest sources of fresh water in the world and are contributing to rising ocean levels. Rising sea levels could expose population centers bordering the ocean to more storm damage and could require evacuation in some areas. But the computer models used for the IPCC report based their predictions only on the results of heating of the existing water in the world's oceans, causing the oceans to expand and sea levels to rise
(3 Feb 2007)
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Global Warming Poses Health Threats
Steven Reinberg, HealthDay via Washington Post
...Michael A. McGeehin, director of the U.S. Centers for Disease Control and Prevention's Division of Environmental Hazards and Health Effects, said, "There are some health effects from climate change that we are comfortable in predicting. We will see an increase in the intensity, duration and frequency of heat waves around the world. We will see more severe precipitation events, both heavy rainfall and severe droughts."
That flooding and drought with bring attendant health problems, McGeehin said. "There are health effects secondary to flooding, such as contaminated water supplies, that could result in the spread of infectious diseases," he said.
Droughts, which are becoming more common and longer lasting, can lead to starvation and the destruction of entire ways of life, particularly in regions -- such as sub-Saharan Africa -- that are least equipped to deal with such catastrophes.
McGeehin also foresees the possible spread of mosquito-borne illnesses such as malaria, dengue fever, yellow fever and encephalitis. "As the climate warms, we may see a change in the range of vector-borne diseases," he said.
(2 Feb 2007)