There is a growing concern among climatologists that the earth may be entering an era of accelerated climate change. This reevaluation has at its core evidence of so-called feedback loops. Some examples of the feedback process are the following:
· As sea ice melts it reduces the albedo effect (reflection of the sun's heat from the surface) and, therefore, leads to an increase in ocean temperature that results in a further melting of the sea ice
· As areas of permafrost – found in Siberia - melt due to increased average temperature in the atmosphere, this releases carbon dioxide (CO2) and the more potent greenhouse gas, methane from vast stores of biomass that exist below the permafrost. It is estimated that the total store of this organic material represent twice the amount of carbon (CO2) already in the atmosphere. The release of these greenhouse gases further increases the average global temperature resulting in further melting of the permafrost. This kind of feedback involving the permafrost has also been implicated in the warming crisis that has been reported to occur at the end of the Permian Period (~ 250 million years ago) by A. Hallam and P.B. Wignall in their book entitled, Extinctions and Their Aftermath
· The disruption of the thermohaline circulation (THC) as discussed in detail in a previous article (Climate Change Revisited). It is important to understand that the THC influences global climate by transporting heat and freshwater between the oceans globally.
The prospect of these feedback mechanisms accelerating climate change has so concerned James E Hansen, Director of the NASA Goddard Institute for Space Studies that he has warned that, "Unless the world slashes CO2 levels back to 350 ppm (the current level is 391), we will have started a process that is out of humanity's control." He cited the possibility of a sea level rise of five meters during this century - if this should become reality it would be catastrophic. Other scientists in his field believe the rise will not be that extreme but do envision a sea level rise as high as two meters. This projection is also very troubling.
These data indicate that not only are we currently feeling the impact of climate change but also that these changes may very well be accelerating. This is a global crisis that necessitates a global solution.
Post a Comment