The following first appeared as a "Letter to the Editor" in today's Washington Post.

In his Feb. 21 op-ed column, "Global warming advocates ignore the boulders," George F. Will concluded, incorrectly, that the Earth isn't warming. Mr. Will referred to climate scientist Phil Jones, who said that the planet did warm from 1995 to 2009 but not "at the 95 percent significance level." But Mr. Jones also cautioned that 15 years is too short to expect statistical significance. That is why climate norms -- such as the "normal" daily temperatures that forecasters show on the local news -- are 30-year averages. The Post's readers might be interested to know, therefore, that the global warming trend from 1980 to 2009 -- a little over 1 degree Fahrenheit -- is statistically significant at the 99.9999 percent level.

Climate scientists have always stated clearly that it takes decades to detect a change in the climate, so why focus on just the last 15 years?

From its own reading of the peer-reviewed literature, the National Academy of Sciences concluded, "It is unequivocal that the climate is changing, and it is very likely that this is predominantly caused by the increasing human interference with the atmosphere. These changes will transform the environmental conditions on Earth unless counter-measures are taken."

Science Q&A

In the past few weeks I’ve posted twice (here and here) on reasons why global warming could be increasing the frequency of heavy snow events in certain parts of the United States (and likely in other similarly situated places around the world).

In a recent post on his WunderBlog (Weather Underground Blog), Dr. Jeff Masters gives his take on this issue. Dr. Masters is co-founder and Director of Meteorology of Weather Underground, a weather service that provides real-time weather information via the Internet. Unlike me, he’s a real weather expert and I highly recommend his blog.

Science Q&A

The cold weather continues across much of the Unites States, Europe, and central Asia as the Arctic Oscillation remains in a strong “negative” state, forcing cold Arctic air down to the mid-latitudes. A couple of weeks ago I explained why more frequent heavy snowfall events could be a consequence of global warming for mid-latitude areas near large bodies of water, like Washington, D.C., and Syracuse, New York (see figure).

On January 31, I noticed a forecast for lake-effect snowfall around the Great Lakes on Weather.com:  “Lake-effect snows are also possible near the central and western Great Lakes today and tonight.”

Science Q&A

On December 19, Washington, D.C. was buried by two feet of snow, setting a new record for snowfall during the entire month of December and paralyzing the city for three days.  As my neighbor and I shoveled out from the storm, he stopped for a moment, grinned, and asked, “So what happened to global warming?” Boy was he surprised when I said, “Glad you asked,” and launched into a 15-minute oratory on why global warming might mean more, not less, extreme snowfall for some parts of the world.

The kerfuffle over email correspondence hacked from a server at the University of East Anglia’s Climatic Research Unit is making climate change deniers giddy.

Scientists to Congress:  You can argue about the politics all you want, but if you decide not to act on climate change, it won’t be because the science wasn’t strong enough.

In a letter sent today, a slew of scientific organizations, including the American Meteorological Society, American Geophysical Union, Crop Science Society of America, and American Chemical Society, informed the U.S. Senate that there is a strong scientific consensus that manmade greenhouse gases are changing the climate and that claims to the contrary are scientifically indefensible:

“Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver. These conclusions are based on multiple independent lines of evidence, and contrary assertions are inconsistent with an objective assessment of the vast body of peer-reviewed science.”

And they go further:  “there is strong evidence that ongoing climate change will have broad impacts on society, including the global economy and on the environment.” They also say the United States will experience significant impacts; climate change isn’t just a problem for poor or developing countries: 

It’s been difficult for average citizens to imagine what global warming means for them. After all, a few degrees of increase in the global mean temperature doesn’t seem too bad. But one consequence that has already been documented is an increase in intense downpours with longer dry periods in between. A recent report from the U.S. Global Change Research Program said,

“Changes in the geographical distribution of droughts and flooding have been complex. In some regions, there have been increases in the occurrences of both droughts and floods.” (p. 18) “The widespread trend toward more heavy downpours is expected to continue, with precipitation becoming less frequent but more intense.” (p. 24)

The historic drought that gripped the Southeast for the better part of two years and the severe flooding that hit the same region last week illustrate this pattern all too graphically.