The Third Annual Global Warming Blog: The Burden of Proof

I’ve been on social media for four years, and I have observed what social scientists have known for much longer: People are driven to make decisions and build personal narratives based more on emotions than facts.  Facts are only accepted if they fit a predetermined view… what is known as confirmation bias.

A recent Time Magazine article illustrates the concept beautifully, even if it highlights the behavior from an uglier political perspective.

As a result, I am still coming to terms with the knowledge that there are people I cannot reach, who do not want to be reached, or believe I have been brainwashed.

I have done my best to be objective about climate change.  I have listened, at great length, to people who do not agree with the mainstream scientific opinion.  In the Internet Age, it is easy to find people who disagree about climate change (or anything else for that matter… but that would be a story for another time).

Rate of Change

The planet is warming. While some level of warming has been going on since the last ice age ended about 10,000 years ago, the observed rate of warming in the last century is without precedent in that time span.  I am convinced now, more than ever before, that the average temperature of Earth is climbing due to the emission of greenhouse (or more appropriately, infrared active) gases.

Multiple lines of evidence indicate the warming is due to an increase in these gases. Carbon dioxide is the most prevalent of them, which has increased dramatically since the latter 19th Century.  The increase is from the burning of fossil fuels.

I blog on this topic once a year, taking in information and slowly digesting it.  The first two blogs were in 2010 and 2011.  I continue to read arguments about how man-made climate change cannot be happening. I find them unconvincing.

The Baseline and Asking Questions

The American Meteorological Society (AMS) revised its climate change statement this year. We are a society of 13,460 scientific professionals, and the Society is trying its best to get it right.  It asked for suggestions from the membership before issuing the statement; it was not dictated to anyone. Do all members agree with every single sentence?  Nope.  But it does represent the current state of the mainstream science.

I always feel the need to learn more. When opportunities came to ask questions directly of those doing the research, I took advantage of them.  I am grateful to the AMS and others (e.g. Bud Ward) who have organized these workshops and conferences, as they have allowed me to speak face-to-face with many professionals in the last 12 months:

I have talked with Kerry Emanuel at MIT about the effects on tropical cyclones. While the strongest ones may get stronger, there will probably be fewer of them. But that is a long way from certain.

I have talked with Tony Broccoli at Rutgers about radiative transfer of carbon dioxide. The level of carbon dioxide is not near radiative saturation. This matches the position from the American Institute of Physics. More simply put, the notion that additional carbon dioxide will have negligible warming effects is false.

I have talked with Judith Lean at the U.S. Naval Research Laboratory about the role of the sun. Solar output does not correlate with the observed temperatures of the past century.

I have talked with Keith Dixon at the Geophyiscal Fluid Dynamics Lab about the imperfections of the general circulation models.  They do a reasonable job of simulating the current climate, so their output gives us important insight into future scenarios.

And after a presentation by the Director of the National Snow and Ice Data Center about 2012’s lowest Arctic Sea Ice Extent of the satellite record (since 1979), I still was not satisfied, so I sent him an email:

Arctic areal ice extent. Blue line indicates 2012, which is more than 2 standard deviations below average.

Dr. Serreze:

You mentioned that we have “good confidence” regarding Arctic sea ice records back to 1950 and “medium confidence” back to about 1900.

Is there anything we can accurately state regarding this year’s Arctic ice minimum with regards to the time before the satellite record?  For example, is it fair to conclude that this season’s minimum is the lowest since 1950?  Or even 1900?



Absolutely it is correct to say we have the lowest ice extent since 1952 (as far back as we can get ice extent for the entire Arctic with high confidence).

I would say that it is very likely that 2012 has the lowest sea ice extent since 1900, the issue here being that our ice charts are not as reliable in the earlier years.

From the viewpoint of climate, there is no reason to think that ice extent at any time since 1900 was lower than today. Yes, there was a warm period from about 1920-1940, but this was largely restricted to the Atlantic side of the Arctic during winter. 

Regarding reconstructions going back further, see the attached short paper; it appears that today’s ice extent is unprecedented over the past 1450 years; this paper also talks about the AMO (Atlantic Multidecadal Oscillation).

The Arctic may have been seasonally ice-free at times during the Holocene thermal maximum (around 7000 years ago) and likely was seasonally ice free during the last interglacial (about 125,000 years ago).

Mark  C.  Serreze
Director, National Snow and Ice Data Center
Campus Box 449
Cooperative Institute for Research in Environmental Sciences
University of Colorado
Boulder CO 80309-0449


Of course, there is a paradox about sea ice at the poles.  In the Antarctic, it is growing (albeit at a much slower rate than the decline in the Arctic).  But the environment there is very different.

Consider Los Angeles and Myrtle Beach. They both get the same amount of sunlight, as they are near the same latitude.  But the adjacent oceans dominate their climates.  Los Angeles (cool Pacific) is temperate and dry.  Myrtle Beach (warm Atlantic) is hotter and more humid. The same issue is at play between the North Pole (Arctic Ocean) and the South Pole (Antarctica).  There are many other reasons why the poles do not respond the same way, including a very recent study from the British Antarctic Survey and NASA’s Jet Propulsion Lab.


Do you remember how warm March 2012 was over most of the country?  Warm spells happen, yes.  But the magnitude of this warm spell was without precedent.  Some of the daily Record Highs were not just broken, but obliterated. Consider these two notes from Jeff Masters’ excellent blog:

First, the Low Temperature at Marquette, Michigan was 52° on March 21, which was 3° warmer than the previous Record High for the date. 

Second, Pellston, Michigan had a record high of 85° on that same day, breaking the previous record for the date (53° in 2007) by 32°, and was 48° above average

What about that cold winter here in Virginia in 2009-2010? While it was among the coldest 15% of winters on record (back to the 1890s), there was only one time when the temperature went below 10° in Lynchburg. That was the morning of January 31, when we reached -2°, at the end of a clear, calm night, immediately following a 9-inch snowfall.

The Average Record Low temperature during the winter in Lynchburg is 3.7°. With that one exception, our lows were always 6 or more degrees above records. Cold was consistent that season, but not intense.

Moving the Averages Ahead

As another analogy, consider the steroid era in baseball.  You could not claim that any one home run was caused because a player was taking steroids, but it sure made a player more likely to hit one. A video clip from the National Center for Atmospheric Research explains further.

There will always be warm and cool spots on the planet, but it has begun to tilt warm. If it were in balance, on the decadal scale, the number of record highs and the number of record lows would be about the same.  From the 1950s-80s, that was the case.

But the numbers started to skew warmer in the 1990s.  And in the first decade of the 2000s, there were twice as many record highs as record lows.  Granted, the figures below are only for the United States, but we are looking at decadal trends, so these numbers are meaningful and significant.

United States Record Highs vs. Record Lows since 1950.

The tilt has started. And while winters will still be cold, and the planet will not turn into Venus, there will be repercussions.  Some places, those repercussions will be worse than others.

Not every part of the climate change puzzle is in place.  But even when piecing together the most complex jigsaw puzzle, there comes a point in time when you see where the end result is going.

If you do not believe the science, then that’s fine.

But to quote astrophysicist Neil DeGrasse Tyson, “Science works whether or not you believe in it.”

Suggested Reading

If you are looking for a non-technical book that presents the current state of the mainstream climate science, I recommend Global Weirdness.  It is actually a bit more level-headed than the title implies.


About seansublette

Meteorologist at Climate Central. Broadcast meteorologist in Virginia from 1995 to 2015. Born and raised in Richmond, VA. Penn State alumnus. Loves baseball and the rock band Rush. Views are independent of my employer. Past performance does not guarantee future results.
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