There are lots of opinions. How does an individual sort the facts? How does the scientific
community determine the truth? If someone tries to convince you that
global warming is as much a scientific fact as that water boils at
100C, they are exaggerating. (By the way there are plenty of conditions that have to be true for water to boil at 100C.)
The scientific community has been building consensus around the
InterGovernmental Panel on Climate Changes (IPCC) Assessments. The
First Assessment Report (FAR) was issued in 1990. Follow up reports are issued every five or six years. The Fourth Assessment Report (AR4) was released in 2007.The fifth Assessment Report is coming in September 2013.
What I am seeing is that there is still a lot of disagreement.
Some of it appears to be sincere. Some may be motivated by political
and economic considerations. There is a lot of effort being
made to convince us there is an overwhelming scientific consensus and particularly in the United States there is a lot of effort being made to convince us that the consensus is not 1) believable (termite mounds and feed lot methane argument), 2) comprehensive (disagreement and scandal) or 3) accurate (Galileo group think argument). A
number of major studies and ongoing evaluations are continuing to
support the theory that something is happening. Why it is happening and
what we can do about it seem to generate the most debate.
It reminds me of the
smoking-cancer debate of the 60's and the Evolution vs Creation debates
that just don't seem to die. There are vested interests and it
will take time to "clear the air." Like that debate there is a lot of
rancor.
- UN's IPCC AR4 concluded that Climate Change is a fact and can be attributed to man-made causes with a 90% probability.
- Mainstream
support for the IPCC consensus is strong. Including the Joint Academies
of Science of the G8 nations, the American Meteorological Society, the
American Geophysical Union and so on. As of July 2007, no remaining scientific body of national or international standing is
known to reject the basic findings of human influence on recent climate.
- The Union of Concerned Scientists provides a nice overview in support of the consensus
- Dr. James Hansen at NASA is particularly concerned that by 2015 global warming will accelerate and become unstoppable. Hansen also claims that the Bush Administration was muzzling scientists.
- IPCC
has their fair share of critics including former assessment report author
and reviewer Christopher Landsea who quit in 2005 claiming politicization of the
science
- Richard
Lindzen (MIT) lead author of Chapter 7 of the 2001 report is sharply
critical of the TAR summary claiming it misrepresents the body of the
report and ignores important disclaimers
- Lindzen wrote an open letter published in the WSJ explaining his position. I think he neatly sums up the whole debate.
Lindzen writes: Our primary conclusion was that
despite some knowledge and agreement, the science is by no means
settled. We are quite confident (1) that global mean temperature is
about 0.5 degrees Celsius higher than it was a century ago; (2) that
atmospheric levels of carbon dioxide have risen over the past two
centuries; and (3) that carbon dioxide is a greenhouse gas whose
increase is likely to warm the earth (one of many, the most important
being water vapor and clouds).
But--and I cannot stress this
enough--we are not in a position to confidently attribute past climate
change to carbon dioxide or to forecast what the climate will be in the
future. That is to say, contrary to media impressions, agreement with
the three basic statements tells us almost nothing relevant to policy
discussions.
- Roy Spencer at the University of Alabama at Huntsville is a key scientist in satellite temperature monitoring. He believes the IPCC is overlooking negative feedbacks that make the climate less sensitive to carbon forcing and will reduce the impact of warming by 75%. He says, "Because small, chaotic fluctuations in atmospheric and oceanic
circulation systems can cause small changes in global average
cloudiness, this is all that is necessary to cause climate change."
- The Skeptical Science website provides a nice summary of the talking points and the science relating to each by focusing on what the peer reviewed science actually says. Skeptical Science is maintained by John Cook, the Climate Communication
Fellow for the Global Change Institute at the University of Queensland.
- S. Fred Singer's
SEPP - Science and Environmental Policy Project is openly critical of the Global Warming
crisis and the only group that that says temperatures have not increased over the past 50 years (see their FAQ)
- The Cato Institute provides a skeptical take on Global Warming
- Richard Wetherald of Geophysical Fluid Dynamics Laboratory, a small branch of NOAA claims that the Bush Administration is muzzling scientists who offer differing points of view. He believes in AGW.
- The libertarian leaning Heartland Institute sponsors an annual International Conference on Climate Change offering primarily skeptics a chance to voice their opinions. These scientists admit warming but argue that solar activity is the dominant driver and predict colder climates ahead.
- According to environmentalists Exxon Mobil
has become a major funder of the most visible "greenhouse skeptics",
most of whom who have traditionally been funded by the coal industry -- including
S. Fred Singer (SEPP), Patrick Michaels (Cato), Robert Balling (Arizona State & Cato) and Sherwood Idso
- Icecap.US website presents a number of contrary papers including numerous Idso's. They think its all a hoax perpetrated by scientists gone wild.
- Sourcewatch
derides Climate Change Skeptics for denial and questions their motives
and funding, but lists 28 individual scientists and pseudo scientists including those above
- William
Gray the nation's hurricane forecaster says Global Warming is a hoax and
that temperatures will drop in the next 5-8 years.
- Author James P Hogan maintains a website full of contrary
information and opinion arguing that the global warming case has not
been proved.
- Bjorn Lomborg, known to many as
'The Skeptical Environmentalist' and named one of the world's 100 most
influential people by Time Magazine, has criticized current expectations of climate
change and the consequences in his book. Lombard is influential for his work on the Copenhagen Consensus which argues for assessing priorities based on cost of the proposed actions. On this scale actions like the Kyoto Protocol rank very low and may even be counterproductive. Lombard publicizes this point in a convincing TED talk.
- JunkScience.com
does a nice job explaining the science from a contrary viewpoint.
Ultimately they agree warming is taking place but suggest solar output
variability as the cause rather than greenhouse gases.
- zfacts.com makes the argument
that we can deal with the threat in some cheap and effective ways while we
finish working out the science.
- clearlight provides a geological perspective that tends to minimize the human influence
- Michael Crichton's best-selling
techno-thriller "State of Fear" is highly critical of the hype
surrounding Global Warming and proposes political control as the motive of some of the GW
promoters. The Union of Concerned Scientists website devotes a page to debunking some of Crichton's claims.
- Al Gore's movie "An Inconvenient Truth" supports GW theory and has returned him to national awareness.
- Lookup American Meteorologists on Wikipedia, sort out the spokesmodels...where do they stand? Wikipedia maintains a nice list of skeptics and their positions.
- There are plenty of books available to suit whatever point-of-view you prefer
- More voices in opposition
- Naomi Oerskes published the most comprehensive survey of opinion. She reviewed 928 peer reviewed papers (refereed journals) on climate change published between 1993 and 2003 and found that 97% of the authors support the consensus.