13 October 2005

False Inferences About Global Warming.



The South Cascade Glacier in Washington State, from the same point of view, from left to right in 1928, 1979 and 2003.

The year 2005 was Earth's hottest year on record, another piece of evidence that adds to the mountain of evidence tending to show that humans are causing global warming.

The Dever Post's conservtive political cartoon, Mallard Fillmore, has been humorously making the case that global warming must be natural because Mars experienced natural global warming this week.

The thing that is annoying about this is that it is pushing very hard on a straw man talking point that is obviously wrong from a scientific perspective. No one doubts that there has been climate change on Earth, Venus and Mars in history. Ice ages and the periods in between are well known in the record of ancient history. But, anyone who looks at the data knows that this doesn't explain what we are seeing now. Why?

Because the pattern of global warming we are seeing now is happening exceedingly rapidly and is closely corrolated with increasing air pollution from human activity. The graph below shows what I mean:



The top graph shows the trend of direct temperature measurements since 1860, the bottom one adds indirect temperature measurements (e.g. tree wrong and ice core based measurements) going back a thousand years. The graph below shows the very close connection between this peak in temperature and carbon dioxide levels which have changed due to human activity.



The National Academy of Science has more here.

As the most comprehensive scientific review of the evidence to date made in 2001 states:

There is new and stronger evidence that most of the Earth's warming observed in the last 50 years is attributable to human activities.


No political argument can be made with footnotes and references to scientific journals. But, making a false assumption, like the idea that global warming supporters haven't considered the possibility that natural climate changes are behind global warming (they have and have found it manifestly implausible), is little more than a lie that leads to bad policy and undermines credibility. Liberals trust solid scientific evidence. Unfortunately, conservative commentators seem to have decided that the truth doesn't matter if they can get people to believe them, and as a result, they have won many political battles. This is one case where I am not willing to copy their tactics to win. The truth is too important. Our commitment to the truth is part of what defines liberals politically.

17 comments:

Sotosoroto said...

Even if the temperature rise is caused by increased C02, and even if the increased C02 is caused by human actions, what can we possibly do to stop it? The Kyoto Protocol is a huge waste of money for a tiny, projected temperature-gain delay. No actual reversal, but just a slowing of the temperature rise. If you're worried about rising oceans, we'd do far better to start building dikes in Bangladesh.

Andrew Oh-Willeke said...

I'd be happy enough if the debate started with a recognition of the scientific facts, and of the fact that if we keep emitting more CO2 that global temperature will predictably rise.

One can legitimately present facts in support of the argument that the economic benefits of pollution outweigh the harms of the global warming is causes (although I wouldn't agree that it is a winning argument, the number of major cities and whole countries that may have to build dikes in short order if we do nothing is huge). But, this post isn't about how we should respond to global warming, it is about dishonesty about scientific facts.

Global warming opponents try to muddy the scientific facts, because they correctly believe that the vast majority of the public would disagree with them if they knew the facts.

Sotosoroto said...

How's this for a fact that the public never hears about? Water vapor controls 95% of the greenhouse effect. 0.001% of the water vapor is caused by human actions. Manmade C02 contributions cause only 0.117% of the greenhouse effect. Is that really enough to make a difference? Or is the natural 99.72% of the greenhouse effect increasing naturally?

Andrew Oh-Willeke said...

Look at the chart. Listen to what the scientists are saying. This is not a scientifically controversial point.

Have water vapor levels in the atmosphere suddenly shot up in the last 140 years? No. Have carbon emissions? Yes. Is there a well established means by which the carbon emissions could cause global warming? Yes, in fact, that factor in climate models is what makes the difference between global warming and no global warming. But, take away the carbon emissions, and you can explain the other temperature changes in Earth's history, but not this one.

CO2 has a much more potent effect on the temperature changes we are experiencing than anything going on with water vapor. Don't take my word for it. Go look at what the scientists at places like the National Academy of Sciences, to which I link, have said on the topic. Water vapor is not responsible for 99.72% of global warming effects right now anywhere but in the head of some sound bite producer.

Sotosoroto said...

I didn't say water vapor was 99.72% of the effect. I said that natural causes were 99.72% of the effect. Humans are only playing with 0.28% of the greenhouse system. I find it very hard to believe that the Earth's ecosystem is so fragile that such a minute change could have a disastrous impact.

Andrew Oh-Willeke said...

The truth, however implausible it may seem, is what remains when all other causes have been ruled out. Natural causes have been ruled out.

Sotosoroto said...

Natural causes have not been ruled out.

The oceans regulate CO2 levels in the atmosphere. A warmer ocean means higher CO2 levels. But what's warming the oceans? If you blame the higher CO2 levels, we got a chicken-and-the-egg thing going. If the system was so unstable to start feeding upon itself with higher CO2 causing warmer oceans causing higher CO2, I think the planet would've crapped out by now.

So we have to look for another reason for the increased ocean temperature. I don't know what it is. Perhaps the Earth's core has hot cycles, similar to sunspots?

Andrew Oh-Willeke said...

The only place natural causes haven't been ruled out is Karl Rove's office.

Sotosoroto said...

Is that the best response you have? I was hoping for some facts...

Dex said...

not everyone gets their own troll. mad props, prophet!

Sotosoroto said...

I'm not a troll. I may be disagreeing, but I'm dead serious.

Julie O. said...

Sotosoroto, could you provide a source for your information? I notice you say water vapor controls 95% of the greenhouse effect, while the National Academies claims it is 66%.

Also, the National Academies that Oh-Willeke links to has information about amplification and feedback...that it's not just natural water vapor and CO2 levels alone, but a combination of things, such as aerosols that affect clouds.

Why human activity is important, I think, is that it is constant. For instance, the difference between natural aerosols from forest fires and manmade aerosols from smokestacks is that forest fires are seasonal, whereas smokestacks go year-round. The feedback and amplification don't vary seasonally and allow the planet to cool itself.

Andrew Oh-Willeke said...

Thanks Julie O., the office server is in and out today, so I'm logging on when it works. You said the kind of stuff that I would have had I taken the time to think about it.

Sotosoroto said...

I googled "global warming 'water vapor'" and the only top site to actually have numbers was Clearlight.com. They list several references at the bottom of their page, which have more data than I can comprehend.

Julie O. said...

It appears that clearlight.com is the only source I could find (cursorily) that says water vapor accounts for 95% of greenhouse gases, and that source has a very obvious agenda.

The National Academies and Wikipedia say it's 66% and 60% respectively, which makes the manmade gases more influential than clearlight.com states.

Read Wikipedia's take on greenhouse gases. It deals a little with feedback, both positive and negative. The warmer water releasing CO2 creating warmer water loop you mention is a negative feedback, which can be mitigated by positive feedback, such as reflective cloud cover.

And positive and negative feedbacks have both natural and manmade contributors. But manmade influences since the industrial revolution have been constant and increasing, whereas natural ones come in cycles, giving the earth time to filter and balance.

Annie said...

While I'd agree that Sotosoroto doesn't seem to have had his sources down pat before quoting their facts, I simply am astounded that anyone here would take W i k i p e d i a as a fully credible, uncontested, bona fide scientific source!!??

I mean, really!

I'm all for reducing pollution even at great cost to us in current generations, but Wikipedia is (even in recent headlines -this being August 2006) being described by its own founder to be suffering from a lack of accuracy and quality.

Warhawke said...

I'm getting tired of reading these posts, trying to find scientific evidence only to find pathetic libel like "Liberals trust solid scientific evidence. Unfortunately, conservative commentators seem to have decided that the truth doesn't matter if they can get people to believe them, and as a result, they have won many political battles." Grow a spine and stop being a coward - fight fire with fire. Conservatives, even assuming that this issue is entirely partisan (which it's not, otherwise I wouldn't be commenting), have just as much claim that global warming doesn't exist as liberals do that it does exist. Otherwise, 17,000 scientists wouldn't have signed a petition AGAINST the Kyoto treaty claiming that independent scientific studies are skewed by personal vendetta and that other studies show nonwarming or even cooling trends.