A Global Warming Primer for Skeptics

Multiple independent lines of data show similar trends

By Shawn Lawrence Otto | Oct 25, 2011 | Comments (8)

Last week climate skeptic Richard Muller reversed his earlier position and, in a Koch-funded study, found that the earth is indeed warming.

This news may have surprised a few readers of the Wall Street Journal, where Muller published an oped, but to scientists it's a reconfirmation of multiple lines of data that have been accumulating for fifty years, all of them pointing to the same conclusion: measurements show the Earth is warming, most likely due to human activities. 

Some Americans still doubt the measurements, even though so many agree that the National Academies now say they should be regarded as "settled facts."  The doubters include some candidates for president, among them Rick Perry, Michele Bachmann, and Herman Cain. 

Skeptics these days come in two varieties.  Some are motivated by a sort of team-sports mentality that has taken over much of American politics.  They argue for whatever the leading Republican pundits say, cheering on the team.  Others are reason-minded and capable of putting America first, but are simply too busy to locate and assess reliable data.  They should consider the following primer.

The Keeling Curve

Charles David Keeling first found a reliable way to measure atmospheric carbon dioxide in the mid 1950s.  During spring and summer, as Northern hemisphere plants grew and soaked up CO₂, the level fell, and in the fall and winter as those plants died off, the level rose.  But something scared Keeling: the overall CO₂ level was climbing.  The Keeling Curve is now one of the most famous images in science and is etched on the wall of the National Academy of Sciences in Washington, DC:

The raw data is available here.

NASA's Global Temperature Readings

NASA's Goddard Institute for Space Studies (GISS) measures global temperatures to create the Global Land-Ocean Temperature Index.  2010 tied 2005 as the warmest year ever recorded.  When deniers, including Rush Limbaugh, were telling people the planet had actually cooled in the last 10 years, that was comparing the 2008 temperature to 1998: 

Here's NASA GISS's raw temperature data.

NOAA's Arctic Ice Extent

NOAA is home to the National Weather Service and has a fleet of satellites that now enable us to create fairly accurate extended forecasts.  The fleet is in jeopardy due to proposed budget cuts in congress - particularly a critical North-South satellite that provides extended forecast data but is also helpful in researching global warming.  Antiscience AGW deniers want to cut that satellite's budget to deprive the public and decision makers of global warming data.  So don't get too used to those extended forecasts - they may go away when the satellite reaches the end of its useful life, in about 2 years.

One thing NOAA does is measure arctic ice extent, which reaches its minimum in September.  2011 is the second lowest ice ever recorded.  As this image from NASA shows, the fabled Northwest Passage even opened up:

Here's the NASA image and article.

Here's the sea ice extent charted over time:

Here is the sea ice extent raw data.

Arctic Open Water Extent

You can take the same ice data and invert it by dividing it into 1.  This will show you the open water extent - the the inverse of the divergence from the 1979-2000 mean ice extent.  What's useful is the graphical component, which you'll see in a minute.

Federally declared disasters

Federal disasters were handled by numerous agencies until they were merged in 1979 into the Federal Emergency Management Agency (FEMA).  Below are the number of federal disasters by year.

Here's the FEMA raw data.

Interesting correlates

Some interesting things happen when you overlay the above charts.  For example, when you overlay open water extent with federally declared disasters, you get this:

This helps to illustrate the increasing correlation between a warmer climate and federal disasters, which are driven by floods, hurricanes, drought and other climate-related events.  

These figures track with the climb in NASA's measured global temperatures:

And all of them are on a similar slope to the Keeling curve:

Your Insurance rates

The similarities are striking, but we are charting different things on different scales, and while that gives us some useful insights, it's got limitations.  So let's try to put all this in dollars.  

What these charts, and atmospheric physics, suggests is that with an increase in temperatures comes a more energetic atmosphere.  It holds more water, so things melt faster, evaporate faster and dry out.  But when it rains or snows we'd expect it to rain or snow harder, though on average less frequently.  In short, we'd expect - on average - a drier climate, wetter and more energetic storms, more runoff, and more flooding.

If such things were happening, we'd expect to get hit with increasing insurance claims.  Let's test that hypothesis.

Munich RE, a major reinsurer of US property and casualty companies, tracks disasters by type:

Here's Munich RE's 2010 Natural Catastrophe Year In review webinar.

While geophysical disasters have remained relatively constant, disasters related to climate change have quadrupled since 1980.  In fact, the losses in coastal states are getting so bad that many private insurers are pulling out and residents must use taxpayer-funded insurance like the troubled Florida Citizens Property Insurance Corporation.

It's a shame that some Republicans have made denying science into a partisan plank.  Such thinking places America's competitive economic future at risk.  It's our ability to deal hard-headedly with science, not our arguing over values, that made America a world leader, and that made the Republican party great.

Fortunately, reasonable people change their thinking all the time when presented with new facts.  When someone tells you they are skeptical about climate change, don't get upset.  Realize that they probably just haven't had time to review the data and are going off third-hand information.  That's reasonable for busy people, but it's putting the nation's environment, grandchildren, and personal fortunes at risk.  So show them this article.  If they are reasonable they should appreciate it.

Get Shawn Lawrence Otto's important new book: Fool Me Twice: Fighting the Assault on Science in America, "a gripping analysis of America's anti-science crisis." --Starred Kirkus Review. An "incredible book" -- Starred Publishers Weekly review. Like him on Facebook. Listen to him of Science Friday. Join ScienceDebate.org to get the presidential candidates to debate science.

Blog Rules