Category Archives: what is global warming?

Global Warming Maps/Graphs

Two years ago I made a post that featured a dozen or so maps and graphs that lended insight into global warming. It turned out to be one of the most read pages on my site. I now want to update that page with even better and a larger number images which are relevant to climate change. They will feature only very brief explanations. Most of what is being shown is self-evident, but if you have questions, feel free to ask them. Hopefully this can serve as a good reference for those who want some images relevant to global warming. I also recommend the site http://www.globalwarmingart.com. These images can all be clicked on for enhanced view. I am also happy to take further suggestions and them.

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Richard Alley at AGU 2009: The Biggest Control Knob

The webcast for Dr. Alley’s presentation is now up, so I recommend watching the video. It is concerning the role of CO2 on climate over geologic time.

As my own side note, Alley is one of my favorite scientists…he’s pretty much “the guy” when it comes to ice core work and has done a lot with paleoclimate (over the ice core record especially), abrupt climate change, glaciology, and sea level rise. He’s a very interesting character who always puts things in a nice perspective, and often humorous ways of teaching (e.g., his Johnny Cash geology lesson).

Re-visiting climate forcing/feedback concepts…

I haven’t been able to post much lately, so I just want to put in this post which outlines some of the basic radiative forcing and feedback physics which climatologists use to assess climate change. This is fairly standard material which should be understood by anyone with a deep interest in climate. This article is a bit lengthy so hopefully you have the patience to go through it (or put it on your favorites and come back). Also, a lot of discussion has come up recently over Richard Lindzen’s ERBE analysis in which he purports to show that global climate sensitivity is small, and that the net effect of climate feedbacks is to dampen the so-called Planck response. That basically provoked this post. I’m going to define all these terms below, so don’t worry if I’ve already lost you, and while I am going to do some math in this post, it should be accessible to most people who know a bit of algebra. Skipping over a few calculus steps won’t be detrimental and I’ve tried not to assume much climate background (although I do link to some side references for clarification on some matters). My focus is not on Lindzen’s analysis here, which I don’t feel to be robust at all, but rather building up simple mathematical models for understanding climate change. This will not be new to anyone who has followed the climate literature or discussions for some time, but hopefully it can be helpful to some, or at the very least, serve as a useful reference.

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Cycles, projections, and other lingo

So I was at work today, and with all the bad weather he had plenty of time to shout at the boss and another co-worker about global warming.  It was a good 2-on-1 handicap match. “Talking” debates are not really my thing since no opportunities exist to check claims, reference sources, show graphs, etc that you could do in online/text correspondence, and so basically anything goes.  Even totally wrong claims like “Volcanoes spit out more pollution than humans do.”

 The boss and the co-worker were very skeptical.  I’m not sure how scientific our exchange was– they spent most of the time trying to convince me I should be very cautious in trusting the general scientific community, and I spent most of the time telling them that they should trust physics, but no one budged.  They’re intelligent group of folk (one trained in biology) but not really familiar with the climate science literature, so I tried to avoid ideas like “radiative forcings,” “water vapor feedback,” “stratospheric cooling,” and other concepts.  So we didn’t really discuss “how CO2 influences climate” or even radiative feedbacks, and it probably was worthwhile as a philosophy of science talk if anything.

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Feedbacks, Sensitivity, and Practical application

The global, annual-mean surface temperature is the most widely used measure of climate change. In particular, scientists are very interested in how the globally averaged temperature will respond as a function of changed amounts of greenhouse gases in the atmosphere, changed amount of solar intensity, etc. The term “climate sensitivity” refers to how much temperature change the planet experiences from a given “forcing.” A forcing is an imposed change of the planet’s energy balance with space.

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Palin on Climate Change

Andy Revkin has a good writeup on the interview between Sarah Palin and Katie Couric. In the interview, Sarah Palin makes many fuzzy points which Andy Revkin (as I) request clarification: what does ‘pollution’ mean? How do we solve a problem if we don’t care what the causes are?

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On the Arctic sea ice

Sea ice extent in the Northern Hemisphere has exhibited large and anomalous declining trends over the last several decades. In particular, there has been over a 20% decline since 1979. Linear trends in arctic sea-ice extent since 1979 are negative in every month.Recently, there has been particular interest recently over a record-breaking year in 2007 which flew by the second-lowest year in 2005. There also has been a foot-race this year, which has kept me particularly interested over the last few weeks. For a while, it seemed that 2008 would clearly not surpass 2007, but due to the drop over the last few weeks, that may not be the case (although it probably will be). Sea ice extent as of September 7, 2008 is 4,739,844 km2, while 2007 minima reached 4,267,656 km2 on September 16th last year.

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