Starting points on Global Warming

A pastor wrote in this week in response to an ESA ePistle post. He had this to say:

"Please send me your proof, not theory, on global warming."

The best emails are short and to-the-point.

I think he must have meant that he wanted proof of human impact on global warming, because no-one really disputes global warming–that’s just a measurement. Actually, I heard a friend say recently he didn’t believe in global warming based on just a few recent years of data–either because 1998 was such a hot year that its temperature wasn’t surpassed until 2005, or because 2006, though hot, wasn’t as hot as 2005. It’s better to look at a longer time period, as the graph from NASA’s Goddard Institute of Space Studies shows. Globalmeansurfacetemps_2There are some wiggles along the trajectory but it’s the 20th century trend that matters most.

Two pilots were coming in for a landing, and they found it very challenging. After they stopped the plane, one of them said "Man, that was a short runway." The other looked from side to side and gawked, "But look at how wide it is!"

Sometimes we look at things at the wrong scale, and forget to see the big picture.

So, the implied question still stands, where the proof that global warming science is true?

I don’t have any sort of "silver bullet" that could "prove" the anthropogenic influence on the climate system. Our current best understanding of global warming is the product of over 100 years of thought and scientific research. We must appreciate the fundamental fact that nothing in science is ever "proven" (which is why we should never place our ultimate faith in any scientific claim). Our complete faith can only be in God as revealed in His word and in His Son!
But science can be very credible, and it can warrant a high degree of confidence. When climate scientists review the vast literature on climate change, as they did last year, they say that they are 90% sure that people are warming the globe. That was the consensus position of all the scientists involved in the Intergovernmental Panel on Climate Change process, which means that even government scientists from Saudi Arabia and the United States agreed. You wouldn’t get even the most convinced scientist to say he’s 100% sure of our current understanding of global warming, just that he’s very, very confident. That’s the nature of global warming science–it’s about the overwhelming preponderance of the evidence, not "proof" in the legal sense.
It’s always hard to know where to point people who really want to grapple with the science, because everyone starts at a different level of understanding.  Going to scientific sources is important, and one should go to scientists actually involved in climate research (not to environmentalists, think-tanks, or even scientists in other fields). Here are some links that would help anyone get started (courtesy of the scientists at http://www.realclimate.org:
For complete beginners:

NCAR: Weather and climate basics
http://www.eo.ucar.edu/basics/index.html

Oxford University: The basics of climate prediction
http://www.begbroke.ox.ac.uk/climate/interface.html

NASA: Global Warming update
http://earthobservatory.nasa.gov/Library/GlobalWarmingUpdate/

Third party (non-science) sources, but still good introductions to the science:

Pew Center: Global Warming basics
http://www.pewclimate.org/global-warming-basics/

Wikipedia: Global Warming
http://en.wikipedia.org/wiki/Global_warming

A little more in-depth, for those with some knowledge:

The IPCC‘s own Frequently Asked Questions (pdf, http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_FAQs.pdf) is an excellent start. That covers:

  • What Factors Determine Earth’s Climate?
  • What is the Relationship between Climate Change and Weather?
  • What is the Greenhouse Effect?
  • How do Human Activities Contribute to Climate Change and How do They Compare with Natural Influences?
  • How are Temperatures on Earth Changing?
  • How is Precipitation Changing?
  • Has there been a Change in Extreme Events like Heat Waves, Droughts, Floods and Hurricanes?
  • Is the Amount of Snow and Ice on the Earth Decreasing?
  • Is Sea Level Rising?
  • What Caused the Ice Ages and Other Important Climate Changes Before the Industrial Era?
  • Is the Current Climate Change Unusual Compared to Earlier Changes in Earth’s History?
  • Are the Increases in Atmospheric Carbon Dioxide and Other Greenhouse Gases During the Industrial Era Caused by Human Activities?
  • How Reliable Are the Models Used to Make Projections of Future Climate Change?
  • Can Individual Extreme Events be Explained by Greenhouse Warming?
  • Can the Warming of the 20th Century be Explained by Natural Variability?
  • Are Extreme Events, Like Heat Waves, Droughts or Floods, Expected to Change as the Earth’s Climate Changes?
  • How Likely are Major or Abrupt Climate Changes, such as Loss of Ice Sheets or Changes in Global Ocean Circulation?
  • If Emissions of Greenhouse Gases are Reduced, How Quickly do Their Concentrations in the Atmosphere Decrease?
  • Do Projected Changes in Climate Vary from Region to Region?

A good resource, often very technical, is a blog maintained by climate scientists

RealClimate: Start with the index,
http://www.realclimate.org/index.php/archives/2004/12/index/

For informed folks who need more detail:

Science: You can’t do better than the IPCC reports themselves
Fourth Assessment Review,
AR4 2007, http://ipcc-wg1.ucar.edu/wg1/wg1-report.html
Third Assessment Reveiw, TAR 2001, http://www.grida.no/climate/ipcc_tar/wg1/index.htm

History: There is a great book on the history of climate change science–Spencer Weart’s "Discovery of Global Warming". It was a cool website associated with it.
http://www.aip.org/history/climate/index.html

2 thoughts on “Starting points on Global Warming

  1. Thank you for your explanation.
    It’s hard to prove something in the world, since you cannot experiment with it. However 99% over the research indicates anthropogenic influence on the climate. This is too easily ignored by ‘skeptics’.

  2. I wonder if the real issue underlying that person’s question is a misunderstanding of what is meant by “theory”.
    The Globe Program has a website focused on ‘citizen science’ projects with schoolchildren. Their chief scientist has a blog that has inclued some climate change items in the past few months – these might help people understand the issues. Start at this post and read some of the more recent ones:
    http://www.globe.gov/fsl/scientistsblog/?p=38

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