As you know, one of my main criticisms of anthropogenic global warming (AGW) theory is that there is not enough thought with respect to the dynamic and self-limiting nature of fossil fuel energy usage and no consideration of technological progress. New clean energy and technology is not fait accompli but it should at least be considered.
Another smaller quibble revolves around the certainty with which many leading advocates for emissions reductions and climate treaties speak. Even though it is often said that climate science is feindishly complex, and it is known that early models were very coarse and sometimes innaccurate, you often hear how the oceans WILL rise, the temperature WILL warm, the storms WILL get worse, the environment WILL collapse, and the changes ARE IRREVERSIBLE.
While these 100% iron-clad statements continue, the science of the matter continues to throw a few curve balls and unearth previously unknown actors in the climate system. For instance, it was recently found that evaporation of water from plants has the potential to slightly cool the planet. It is well known that plants can cool a small area through evaporation because evaporating water takes energy. Our bodies even use this process (evaporation through sweating) to keep cool. What was not known as well in the past is the potential for evapotranspiration (from plants) to form low clouds which reflect the sun’s energy back into space. This would cause a slight cooling effect. If moisture and precipitation continue to increase in the near future, then the slight cooling effect could continue and should be considered in future projections.
Another research effort has found that molecules called biradicals can cool the atmosphere. These molecules form in the atmosphere when ozone reacts with other molecules comprised of carbon and hydrogen. What forms is a type of aerosol that reflects the sun’s radiation back into space. It is unknown how much cooling effect this natural and sometimes unnatural (where there is smog/ozone in cities) molecular process has on the atmosphere.
As far as modeling the future climate, there are still some holes that need to be plugged in order to improve the accuracy. A recent paper from the Pacific Northwest National Laboratory pointed out some room for improvement in predicting arctic sea-ice loss. Arctic clouds play a big part in how much sea-ice melts every Summer and current models do not completely capture the amount of arctic cloud-cover or the amount of radiation they reflect. Knowing the atmosphere-ice-ocean feedback processes in greater detail should improve future climate forecasts.
Amazing as it might seem, it is also still not known whether forests contribute to AGW or help mediate it. On the surface you would think that trees would take more carbon out of the atmosphere, they are after all “made” out of carbon (and other elements, of course). Due to complex feedbacks of growth and decay, tropical forests might have a much different effect on atmospheric carbon dioxide that boreal (far north) forests. Also, northern forests might not be absorbing as much carbon as previously thought, especially in areas where warmer weather has also meant drier weather, such as western Canada.
None of this means that climate science is complete bunk. The climate models are based on well known chemical and physical processes. Certain molecules such as carbon dioxide, water vapor, and methane are well known to have an effect on temperature and radiation transfer. Humans most likely have an effect on the long term climate. However, there is not 100% certainty of environmental Armageddon. Our certainty does increase every year as more data becomes available but the climate system is dynamic and heretofore unknown triggers could tip temperatures in different directions. Many climate scientists think the variation in the sun’s energy output does not have an effect on our current climate, but it is unknown whether tiny changes in solar output could be amplified within the earth’s climate system to produce unexpected results.
In addition, future technological progress will likely assist us in reducing our impact on the environment and atmosphere. There will not be “business as usual” fossil fuel usage all the way through 2100. Be sure to keep your eye open for more efficient devices, housing, and vehicles. You can save money and lessen pollution at the same time.
Have a good Wednesday! Meteorologist Justin Loew.
This post was written by jloew on February 8, 2012