Hey, wait a minute, weren't scientists warning us of an impending ice age back in the 1970s?

Beginning in 1970, there was considerable media attention given to speculation that Earth would soon see a new ice age. A scientific paper published in 1971 by S.I. Rasool and S.H. Schneider at the Institute for Space Studies is often cited as predicting an ice age. The paper was about the effects of aerosol levels in the atmosphere; the authors speculated such levels would rise by 600 to 800 percent over the next few years, and that this would trigger an ice age. What actually happened was that aerosol levels fell. Even if they hadn't, many scientists believe that Rasool and Schneider were inaccurate in their estimates about how carbon dioxide levels affected temperatures. Nevertheless, this publication and others that cited it drew the attention of the media, leading many people to believe that the next big climactic change would be a cooling off period.

Do other scientists believe we may be heading for an ice age?

Yes. In 2006, for example, chief researcher Khabibullo Abdusamatov at the Russian Academy of Sciences said that he believed worldwide average temperatures would

Could a sudden ice age like the one in the 2004 movie The Day after Tomorrow actually result from global warming?

No. That's Hollywood. In the movie, a scientist predicts (correctly for the plot of the film, which provides a lot of opportunities for special effects) that all the fresh water melting into the oceans will cause the Gulf Stream to dissipate, and that this will lead to the sudden onset of a new ice age. New York City freezes over in a day, and bizarre storm cells cause people to turn into popsicles in seconds. Ridiculous, say experts, though they admit that ice caps melting will indeed cause many adverse effects, such as rising oceans and changes in weather patterns.

That said, it is interesting to note that ice ages can occur fairly quickly. Geologists and glaciologists estimate that some ice ages made significant advances through North America in spans ranging from a few decades to as little as three years.

slowly decrease from 2012 to 2015, and then in the middle of this century there would be a much more precipitous drop in temperatures that would last for 60 years.

I heard that some glaciers in Alaska are growing, not shrinking. Is this true?

It's true that many Alaskan glaciers, including, most notably, the Hubbard Glacier, have been advancing in recent years. The reasons for this are complex and may have nothing to do with whether or not climate change is occurring. To simplify what is the rather complicated science of glaciology, there are different types of glaciers. Some glaciers rest in valleys and tend to be more sensitive to changing temperatures. Others, including Hubbard, are known as calving glaciers. They terminate at an ocean and parts of them break away in a stunning spectacle known as "calving." The five large glaciers in Alaska that are growing, including Hubbard, all have several commonalities: 1) they have previously experienced long periods of retreat only recently reversed (in the past century or so); 2) they all calve on shallow moraine shoals; 3) they all lay at the heads of long fjords; 4) they have positive mass balances that, by sheer force of weight, cause them to expand as gravity pushes down on them; and 5) they have small ablation areas; that is, small surface areas where melting and sublimation occur. Glaciologists note that glaciers with these qualities are not strongly influenced by even long-term temperature changes.

What petition have thousands of scientists signed that says that global warming is not caused by people?

Over 31,000 American scientists have signed the Global Warming Petition, which states that global warming is not caused by human activities, that there are actually many benefits to having a warmer planet, and that the United States should con

Glacier calving in Glacier Bay, Alaska, is a natural process; however, it seems to be accelerating as glaciers melt faster because of global warming. (photo by John Bortniak, NOAA Corps)

tinue to reject the Kyoto Protocol. Looking at trends in such areas as ocean temperatures, solar activity, glacier shrinkage, and severe storm events, these scientists assert that upwards trends in all of these areas have been occurring since the 1800s. They believe, therefore, that policies limiting industrial and economic development are misplaced.

What was the weather like in China in 2008?

The winter of 2008 was one of the coldest on record in China. Even cities in South China, including Hong Kong, experienced record lows and power outages that sometimes lasted weeks. Over 100 people died as a result of the frigid weather.

Wasn't 2008 one of the coolest years for the United States?

Yes, for the United States the 2008 temperature averages were the lowest since 1997. Also, precipitation was way up that year, which, along with it being a La Niña year, is a primary reason why meteorologists believe it was a considerably cooler season. The average temperature from January to October 2008 was 55.9°F (13.3°C) versus 55.7°F (13.2°C) in 1997. This made 2008 actually a fairly average year with regard to records kept over the last 114 years. However, global temperatures were the ninth highest on record in 2008.

What has the National Climatic Data Center reported about average temperatures in 2008?

According to the NCDC, the average temperatures for the contiguous 48 U.S. states was 0.3°F (0.14°C) cooler than the average measured from 1900 to 2000.