Putting aside the fantastical nature of the speed with which this happened, the base science is sound; that an increase in freshwater could slow or shutdown the thermohaline circulation, causing an unexpected and unhelpful ice age.

Read more of this story »

An article in Canada’s National Post summarized weather around the northern hemisphere and concluded that arctic ice is back, heavier than ever in some areas, and China is reeling from its worst winter in a century.

Of course, it doesn’t mean global warming is a non-entity, nor does it mean we’re headed for a mini ice-age. The author, Lorne Gunter, took a swipe at environmentalists this way:

“Ok, so one winter does not a climate make. It would be premature to claim an Ice Age is looming just because we have had one of our most brutal winters in decades.

But if environmentalists and environment reporters can run around shrieking about the manmade destruction of the natural order every time a robin shows up on Geeorgian Bay two weeks early, then it is at least fair game to use this winter’s weather stories to wonder whether the alarmist are being a tad premature.”

Read more of this story »

Fact: No, they didn’t. The situation in the 70’s was very different from our current situation. There was no scientific consensus on climate change. There was no international body of scientists looking into the matter, no global effort to deal with climate change, and no daily news articles on the subject. There were maybe a couple of magazine articles, a book, and some sporadic newspaper articles.

Today, by contrast, we have the IPCC, an organization of the world’s top climate scientists and its four reports, the latest of which claims with 90% certainty that anthropogenic greenhouse gas emissions are primarily responsible for our current warming. We also have other scientific bodies that agree with this assessment, such as the National Academy of Sciences and the American Association for the Advancement of Science. Should one ask for a scientific paper from that time period that makes such a claim, one would certainly be left empty-handed. The most common example used is an article that was published in Newsweek in 1975, titled "The Cooling World", which provides an excellent example of the sensationalist reporting that existed within some media reports.

The situation was also different because the state of climate science was such that there was not enough research to be able to make these supposed predictions with any certainty. A 1975 National Academy of Sciences report stated as much, saying "…we do not have a good quantitative understanding of our climate machine and what determines its course. Without the fundamental understanding, it does not seem possible to predict climate…". Climate science was in its infancy. There wasn’t yet enough data or research available on which to base such a prediction, and scientists were well aware of that fact. Scientists’ current statements on the future of our climate are based on decades of research and massive amounts of data that has been collected over that time.

Also, as the climate scientists at RealClimate have pointed out, we know that climate scientists could not have made such predictions based on the scientific information that was available at the time:

Firstly, there was a trend of cooling from the 40’s to the 70’s (although that needs to be qualified, as hemispheric or global temperature datasets were only just beginning to be assembled then). But people were well aware that extrapolating such a short trend was a mistake (Mason, 1976) . Secondly, it was becoming clear that ice ages followed a regular pattern and that interglacials (such as we are now in) were much shorter that the full glacial periods in between. Somehow this seems to have morphed (perhaps more in the popular mind than elsewhere) into the idea that the next ice age was predicatable and imminent. Thirdly, there were concerns about the relative magnitudes of aerosol forcing (cooling) and CO2 forcing (warming), although this latter strand seems to have been short lived. - RealClimate

This argument, like many other skeptical arguments, is simply an ad hominem attack. Rather than addressing the merits of the science behind anthropogenic global warming, it attempts to discredit climate scientists in general based on arguments and statements they never made. Such arguments hold about as much merit as recent attacks against Al Gore and claims that previous high levels of carbon dioxide in our atmosphere were caused by dinosaur farts. If there were any valid points to be made by skeptics, this would not be one of them.