A recent letter writer pointed to the natural effects of water vapor and carbon dioxide in the greenhouse effect on earth, and to the fact that climate change has been happening as long as earth has been in existence. Both of these are correct statements.
In fact, natural climate change has been a topic of scientific research for around 200 years. Earth scientists have characterized very well a wide range of natural climate variations, which occur with different time scales and intensities.
It is precisely this understanding that provides the basis for the strong conclusion that changes that are happening now are not natural.
The changes correspond to increases in carbon dioxide in the climate system that track closely the emissions from fossil fuels. Contrary to what the previous writer asserts, humans are already altering a natural phenomenon.
Thousand of peer–reviewed scientific papers have been published on the topics of both natural and human-caused climate change. Much of this knowledge is summarized in the recent National Climate Assessment and in the reports of the Intergovernmental Panel on Climate Change (www.ipcc.ch).
Climate scientists must demonstrate their conclusions through the peer-reviewed process, with data and models being independently reproducible and transparent.
The previous writer is encouraged to submit their work to the rigorous process that the scientific community has established, in order to demonstrate their conclusion that all climate change is natural.
It behooves us to use the knowledge gained from science to make the best long-term decisions.
Greg Valentine, Ph.D.