Don't sell your coat
Our severe winter has some global warming advocates in hiding. But this is just weather, not climate, as other parts of the earth are warmer than usual. Projecting the world’s climate future remains a challenge for our best computer models.
There are several government agencies that measure global temperature trends. They are all showing the current 15 year ‘pause’ in our longer term global temperature rise since the Little Ice Age. Most climate scientists think that some of our missing heat is being stored deep in the oceans.
I suggest that another explanation for this recent pause is influence from the 30-year Pacific Decadal Oscillation cycle, which is in the middle of a Pacific Ocean surface cooling phase. This suggests about 15 more years of flat to cooling global temperatures. As the cooling phase ends, we could then resume warming with help from the new carbon dioxide we have dumped into the atmosphere.
The earth is currently on a slow irregular temperature rise, as we gradually recover from the Little Ice Age which ended about 1800 A.D.
There is a much longer climate cycle which is caused by earth orbital changes. Those orbital cycles have brought us several large Northern Hemisphere glaciers, each lasting about 100,000 years, during the past million years. In between we have a shorter inter-glacial warm period.
We could well have another big glacier when the current inter-glacial period ends. Don’t sell your winter coat.
Rolf E. Westgard
ROLF E. WESTGARD writer recently taught the class “America’s Climate and Energy Future” for the University of Minnesota Lifelong Learning program.