When it comes to global cooling (I can remember when we were being told we were heading into another ice-age), the is a simple explanation as to why it didn't happen: the computers used to run the simulations and to make the predictions were rubbish. The scientists involved in the research will freely say "we punched the numbers in and that's what the computers came up with, they just weren't powerful enough to model what would actually happen". Malkes you wonder if this will be said again in 20 years?
This, with a caveat on the last line.
It's the thing people don't seem to understand (or ignore, unless it suits them otherwise) about scientific research, which is that it's okay to be wrong and decide that a different outcome is more likely.
Global warming is more likely, given that it's actually happening, as supported by the data (note: I'm referring to global warming due to
any cause, not just humans).
The data compiled in the 70s also didn't take into account the damage we did the the ozone layer in the 1980s which did its fair share for warming the Northern hemisphere. You can kind of forgive the scientists in the 70s for missing that one. Research can be used to predict things but it's not psychic.
As for what'll happen in another 20 years, the reliability of modern data makes any vast change from current estimates much less likely. That is, unless there's some big catastrophic event in the next 20 years, or some huge breakthrough in technology that changes our impact on the planet, both of which could feasibly make current estimates inaccurate.
As an aside:
A program I was watching the other day reminded me of the old "volcanoes produce more CO2 than humankind" argument.
I never genuinely knew the answer to this but it provoked me into doing a little research when I saw the TV program. Found these numbers on the website of the
Hawaiian Volcano Observatory:
Our studies show that globally, volcanoes on land and under the sea release a total of about 200 million tonnes of CO2 annually.
This seems like a huge amount of CO2, but a visit to the U.S. Department of Energy's Carbon Dioxide Information Analysis Center (CDIAC) website (
http://cdiac.ornl.gov/) helps anyone armed with a handheld calculator and a high school chemistry text put the volcanic CO2 tally into perspective. Because while 200 million tonnes of CO2 is large, the global fossil fuel CO2 emissions for 2003 tipped the scales at 26.8 billion tonnes. Thus, not only does volcanic CO2 not dwarf that of human activity, it actually comprises less than 1 percent of that value
The counter for 2011 on
Worldometers is reading something over 28 billion tons so far this year.
Obviously CO2 is only
one of the greenhouse gases, and not the strongest, but interesting nonetheless. Puts a myth to bed at least.