April 30, 2009

What You Can(‘t) Do About Global Warming

We are always hearing about ways that you can “save the planet” from the perils of global warming—from riding your bicycle to work, to supporting the latest national greenhouse gas restriction limitations, and everything in between.

In virtually each and every case, advocates of these measures provide you with the amount of greenhouse gas emissions (primarily carbon dioxide) that will be saved by the particular action.

And if you want to figure this out for yourself, the web is full of CO2 calculators (just google “CO2 calculator”) which allow you to calculate your carbon footprint and how much it can be reduced by taking various conservations steps—all with an eye towards reducing global warming.

However, in absolutely zero of these cases are you told, or can you calculate, how much impact you are going to have on the actual climate itself. After all, CO2 emissions are not climate—they are gases. Climate is temperature and precipitation and storms and winds, etc. If the goal of the actions is to prevent global warming, then you shouldn’t really care a hoot about the amount of CO2 emissions that you are reducing, but instead, you want to know how much of the planet you are saving. How much anthropogenic climate change is being prevented by unplugging your cell phone charger, from biking to the park, or from slashing national carbon dioxide emissions?

Why do none of the CO2 calculators give you that most valuable piece of information? Why don’t the politicians, the EPA, and/or greenhouse gas reduction advocates tell you the bottom line?

How much global warming are we avoiding?

Embarrassingly for them, this information is readily available.

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April 15, 2009

Climate Models: Better Clouds=Less Warming?

While all the attention has been focused on a paper by Warren Washington and colleagues that has just been accepted by the scientific journal Geophysical Research Letters (GRL), whose conclusions can perhaps best be summarized by “Yes, Virginia, there is something you (acting together with 7 billion of your closest friends) can do to lessen climate change,” another paper has been published by GRL that seems to argue that if climate models had a better handle on the true behavior of clouds, that they may project less warming than they do now.

So, perhaps Virginia, if you wait for the scientists to get things right, there may be less that you actually have to do in the first place (which is a good thing, because according to the Washington et al. results, you are way behind already).

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April 8, 2009

Has the climate recently shifted?

“Has the climate recently shifted?” is the title of a just-published paper in Geophysical Research Letters by researchers Kyle Swanson and Anastasios Tsonis from the University of Wisconsin-Milwaukee. Their examination of this topic was undoubtedly prompted by the recent behavior of global temperature which shows that the rate of warming has dramatically slowed during the past 7-12 years.

Updating a methodology that they had previously developed and used to identify several changes in the climate state that occurred during the 20th century, Swanson and Tsonis examined the temperature data from recent years to see if another state change had taken place:

Here, a new and improved means to quantify the coupling between climate modes confirms that another synchronization of these modes, followed by an increase in coupling occurred in 2001/02. This suggests that a break in the global mean temperature trend from the consistent warming over the 1976/77–2001/02 period may have occurred.

In other words, the authors think that they have identified another in a string of break points that signal a change in the general state of the earth’s climate.

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March 5, 2009

Feedbacks and Climate Sensitivity

A week or two ago, Andrew Dessler and Steven Sherwood published a “Perspectives” (largely opinion) piece in Science magazine that argued that the water vapor feedback was unassailably strong and positive. This means that the warming from the increase in greenhouse gas concentrations leads to more water vapor in the atmosphere which leads to even more warming (water vapor is a strong greenhouse gas itself). This positive feedback results in roughly twice as much warming as would occur from anthropogenic greenhouse gas increases alone.

Dessler and Sherwood concluded:

There remain many uncertainties in our simulations of the climate, but evidence for the water vapor feedback—and the large future climate warming it implies—is now strong.

This conclusion has drawn a lot of attention within the community of researchers investigating the behavior of water vapor and the role of water feedback in climate change—and most of it has been highly critical.

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February 13, 2009

Subcommittee on Energy and Environment Testimony

On Thursday, February 12, 2009, Dr. Patrick J. Michaels provided testimony to the U.S. House of Representatives Subcommittee on Energy and Environment during their hearing “The Climate Crisis: National Security, Public Health, and Economic Threats.”

Dr. MIchaels’ general message was that the recent behavior of global temperatures is starting to push the (lower) bounds of climate models’ expectations of such behavior and that if the current slowdown in the rate of global warming continues for much longer, we must start to question the reliability of climate projections of the future state of our climate.

His complete written testimony in included below:

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December 3, 2008

Rethinking Observed Warming

The United Nations Climate Change Conference is underway this week in Poznan, Poland, and literally thousands of folks have convened and reinforced the notion that the buildup of greenhouse gases has caused substantial warming in recent decades and that left unchecked, the continued buildup will undoubtedly cause significant warming in the decades to come. Believe it or not, it is possible that aspects of the traditional greenhouse gas explanation could be largely wrong, and if you think we are crazy, let’s visit an article just published in the prestigious journal Climate Dynamics.

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February 21, 2008

Global Warming: Not So Fast

For more than 100 years, climate scientists have fully understood that if all else were held constant, an increase in the atmospheric concentration of carbon dioxide (CO2) would lead to an increase in the near-surface air temperatures. The problem becomes a lot more complicated in the real world when we consider that “all else” cannot be held constant and there are a lot more changes occurring at any one time than just the concentration of CO2. Once the temperature of the Earth starts inching upward, changes immediately occur to atmospheric moisture levels, cloud patterns, surface properties, and on and on. Some of these changes, like the additional moisture, amplify the warming and represent positive feedback mechanisms. Other consequences, like the development of more low clouds, would act to retard or even reverse the warming and represent negative feedbacks. Getting all the feedbacks correct is critical to predicting future conditions, and these feedbacks are simulated numerically in global climate general circulation models (GCMs). Herein lies a central component of the great debate — some GCMs predict relatively little warming for a doubling of CO2, and others predict substantial warming for the same change in atmospheric composition.

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August 14, 2007

The Iris Opens Again?

Back in 2001, Richard Lindzen and colleagues made quite a stir in the climate community when they published a paper in the Bulletin of the American Meteorological Society in which they describe having possibly identified an “adaptive infrared iris” that opens and closes to keep the earth’s temperature fairly steady even in light of increasing atmospheric carbon dioxide levels. It was proposed to work something like this—when the temperature in the tropical oceans begins to warm up, it causes in increase in the amount of low-level water clouds and an even greater decrease in total coverage of high-altitude ice clouds. Since ice clouds are net warmers (that is, they trap more outgoing longwave radiation (heat) than they reflect away incoming shortwave (solar) radiation) and water clouds are (generally) net coolers (reflecting back to space more incoming solar shortwave radiation than they absorb outgoing longwave radiation), more of the latter and a lot less of the former leads to a net cooling, and the temperatures of the tropical oceans decrease. However, cooler tropical ocean temperatures lead to less low-level (water) clouds and more high altitude ice clouds. This configuration tends to lead to a net radiation increase and to higher temperatures. And the cycle starts over again. Lindzen’s moniker “adaptive infrared iris” refers to the mechanism in which the tropical ice cloud cover opens and closes in response to tropical ocean temperatures to allow more heat to escape to space when the oceans are warm and less heat to escape to space when the oceans are relatively cool (much like the iris of an eye which opens and closes in response to varying light levels to try to maintain a constant level falling on the retina). Lindzen et al. proposed that the iris acts as a global thermostat that will keep the earth’s temperatures from rising very far even as atmospheric concentrations of greenhouse gases increase.

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November 27, 2006

Dimming Fights Drought?

A recent article in Geophysical Research Letters by Rutgers’ scientists Alan Robock and Haibin Li addresses the issue of global warming and reduced soil moisture levels in important agricultural areas. Every popular global warming presentation lays out the case that higher temperatures in the future will cause higher levels of evaporation that will overwhelm any changes in precipitation and force soil moisture levels to drop. Of course, crops will fail, we will have more frequent and severe droughts of longer duration, and it will have all been caused by elevated carbon dioxide (CO2) levels. You’ve heard the story a 1,000 times by now.

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November 2, 2006

Messy Models

The global warming scare comes largely, if not exclusively, from the outputs of numerical climate models. Some of the models are relatively simple in their design while other climate models are among the most sophisticated computer programs ever built. When the concentration of greenhouse gases is increased numerically, almost all models of climate show an increase in global temperature with the most warming occurring in the Northern Hemisphere’s highest latitudes. Predictions involving precipitation, drought, hurricanes, floods, changes in climate variability, and all the rest vary considerably from model to model. Many greenhouse advocates treat the 2 ×CO2 model simulations as predictions for the future with little regard for shortcomings in the way the models numerically represent the 1,000s of complex processes at work in the climate system.

The Intergovernmental Panel on Climate (IPCC) change warns in their Summary for Policymakers “models cannot yet simulate all aspects of climate (e.g., they still cannot account fully for the observed trend in the surface-troposphere temperature difference since 1979) and there a particular uncertainties associated with clouds and their interaction with radiation and aerosols.” Two articles have appeared in the scientific literature recently that further expose the weaknesses in the model simulations.

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