My in-laws were visiting our new home last week, and we decided to take a trip to Washington, D.C. to see the Smithsonian. One of the museums we visited was the Museum of Natural History. In an otherwise very well done museum, we came across this display in the section called "Ice Age."
If you can't read the text, here is what it says:
Ice ages include both warm and cold periods. We are now in a relatively warm period ("interglacial") following on of several major glacial periods. It is not certain when the present interglacial will end, but the period of 1890-1945 A.D. was abnormally warm, and there have been signs of cooling in the last decades.
The cause of these dramatic changes are not clear, but they are important to all ? [obscured - probably life] for even minor climatic changes affect the world's population in major ways. Imagine the impact on food and heating resources alone - of another full-scale glacial advance like that one shown on the world map (beyond) just a few thousand years ago!
Let me say - I'm not a climate scientist. I figure they are probably referring to the aerosol effect from CFCs (responsible for the ozone hole) here. In the late 70s/early 80s there was discussion about "global cooling" from the massive amounts of CFCs we were putting in the atmosphere. The global warming that was occurring was probably masked by this effect. Interestingly, the world actually addressed this problem with the Montreal Protocol (back in the days that the U.S. participated in treaties on climate).
The display talks about other ice ages, and changes that may have led to them, like changes in the earth's orbit ("wobble") and changes in the amount of sunlight reaching the earth. There was no discussion about carbon dioxide or human contributions to our atmosphere. I did not see the whole museum (a good chunk, though) but I did not see any displays at all about global climate change. Here's a map of the museum, do you think a discussion would be located in another section?
So, concern about a second ice age may have been valid 25 years ago - but haven't they had time to correct the record at the Smithsonian - our national museum - yet? The other exhibits - about evolution and the origins of life, the fossil record and gems & minerology are all excellent, why is global warming absent? In 2005, the Smithsonian hosted Michael Crichton talking about his book State of Fear. When I searched the museum website for "global warming" several reports popped up. According to their 2006 report there was an exhibit about the changes in the arctic, but it was not present at the museum and the Ice Age exhibit had not been changed to reflect this. So, I don't think the Institute is really denying its existence, but why don't the exhibits reflect this? This is one of the biggest issues of the day, which affects the whole planet (like the plaque said, it affects all life).