Bjorn Lomborg on global warming

I read an interesting article about Bjorn Lomborg in the New York Times [link].  Lomborg will get a lot of media attention in the coming weeks, and I recommend approaching the skeptic with skepticism.  

I was originally going to post this article with positive comments about Lomborg, but upon looking just a bit closer, I found deep problems with what was quoted in this article alone.  Let's have a closer look, shall we?

Since record-keeping began in the 19th century, the sea level in New York has been rising about a foot per century, which happens to be about the same increase estimated to occur over the next century by the Intergovernmental Panel on Climate Change (IPCC).

This is tricky because sea levels don't rise equally everywhere (that might sound silly, but consider the fact that the height of the land can change locally).  Say we take for granted that the above is true for New York.  

Then the natural question is: are sea levels expected to rise globally at the same rate as they did in the past century?

The answers are in the IPCC report Climate Change 2007: The Physical Science Basis - Summary for Policymakers (PDF link).

Globally, the average sea level has risen about 17 centimetres in the past century - about half a foot (see page 7 of the IPCC report).

As to how much sea levels are expected to rise, that's a bit more complicated.  The IPCC doesn't just make one prediction for the next century - there are just too many different things that can happen in a century.  Instead, they make a series of predictions, each based on different scenarios.

In some scenarios, the world focuses more on rapid economic growth, and in others the world focuses more on ecology.  In some, globalisation makes people, ideas, and technologies very mobile.  In others,the world becomes more fragmented.  Different scenarios have different levels of reliance on fossil fuels, and different patterns of population growth, energy use, technology, and so on.  Predictions are usually given for six scenarios.

In the best-case scenario - the more integrated, more eco-friendly world - the estimate is that sea levels will rise between 18 and 38 centimetres.   In the world with rapid economic growth relying heavily on fossil fuels, the estimate is between 26 and 59 centimetres (see page 13 of the IPCC report).  

So, is the predicted rise for the next century equal to the rise in the past century?   

The short answer is 'no'.

The long answer is:  The low-end of the error bar on the prediction for the best-case scenario overlaps with the high-end of the error bar for the rise in the past century.  In the other, more realistic scenarios, there is a much bigger difference.

Onto another of the articles amazing claims:

He calls Kyoto-style treaties to cut greenhouse-gas emissions a mistake because they cost too much and do too little too late. Even if the United States were to join in the Kyoto treaty, he notes, the cuts in emissions would merely postpone the projected rise in sea level by four years: from 2100 to 2104.

Years ago, Lomborg made a similar claim in his previous book, The Skeptical Enviromentalist.  

Scientific American published a rebuttal to the book, which addressed that claim.  Stephen Schneider writes:

[Lomborg argues that] the Kyoto Protocol, which caps industrialized countries' output of greenhouse gases, is too expensive. It would reduce warming in 2100 by only a few tenths of a degree--"putting off the temperature increase just six years." This number ... is based on a straw-man policy that nobody has seriously proposed: Lomborg extrapolates the Kyoto Protocol, which is applicable only up to 2012, as the world's sole climate policy for another nine decades.

Just to make that clear: Lomborg's projection is based on the scenario where the Kyoto Protocol is enforced, but nothing else is done after that.  

Schneider again:

Every IPCC report has noted that carbon dioxide emissions need to be cut by more than 50 percent below most baseline projections to avoid large increases in concentration in the late 21st and 22nd centuries. Most analysts know "Kyoto extended" can't make such large cuts and that both developed and developing nations will have to fashion cooperative and cost-effective solutions over time. This will take a great deal of learning-by-doing: international cooperation is not a common experience. Kyoto is a starting point. And yet Lomborg, with his creation of a straw-man 100-year projection, would squash even this first step.

---

This is not to say that everything Lomborg's saying is baseless.  But sometimes you need to consider the assumptions he works on.  For example:

Hotter summer weather can indeed be fatal, as Al Gore likes us to remind audiences by citing the 35,000 deaths attributed to the 2003 heat wave in Europe. 

But ... winter can be deadlier than summer. About seven times more deaths in Europe are attributed annually to cold weather (which aggravates circulatory and respiratory illness) than to hot weather, Dr. Lomborg notes, pointing to studies showing that a warmer planet would mean fewer temperature-related deaths in Europe and worldwide.

The second factor is that the weather matters a lot less than how people respond to it. Just because there are hotter summers in New York doesn'€™t mean that more people die — in fact, just the reverse has occurred. ... [The] number of heat-related deaths in New York in the 1990s was only a third as high as in the 1960s. The main reason is simple, and evident as you as walk into the Bridge Cafe on a warm afternoon: air-conditioning.

Lomborg argues that global efforts should focus not on reducing global warming, but on economic development.

If you'™re worried about stronger hurricanes flooding coasts, he says, concentrate on limiting coastal development and expanding wetlands right now rather than trying to slightly delay warming decades from now. To give urbanites a break from hotter summers, concentrate on reducing the urban-heat-island effect. If cities planted more greenery and painted roofs and streets white, he says, they could more than offset the impact of global warming.

He's done cost-benefit analyses, and concluded that the money would be better spent on fighting malaria, aids, malnutrition, and poor drinking water.

All of this makes sense as an argument.  But it's based on two unspoken assumptions that I personally don't buy.

First is the assumption that the only important costs of global warming are the human costs.  Safeguarding cities and helping people afford air-conditioners would help us out, but it doesn't do anything about the ecological effects.  Extinct animals, destroyed ecosystems: none of these seem to factor as important.   Even if the natural world would bounce back eventually (which I'm certain it would), there remains the question of whether it is right to destroy it now.

The other assumption is that there is one big purse of money that we can either spend on fighting global warming or fighting all other ills.  This is a false dilemma.  The world can, and does, spend money on both.  Yes, a dollar spent on fighting global warming is a dollar you could have spent fighting malaria, aids, or malnutrition.  But the same goes for any dollar you spend.  Why single out global warming?

---

Bjorn Lomborg is very good at appearing credible.  By appearing to stake out the middle ground, he makes it hard to criticise him without seeming like an extremist.  I've just picked apart that entire article, for example, and it's made me really self-conscious about looking like a zealot.  But there really is nothing, in that article at least, to suggest that he's anything but a garden variety anti-global warming pundit, throwing about carefully-chosen factoids.  He doesn't seem to be in the middle ground at all.

I'm keeping an open mind about him, though, because there's always the chance this article didn't do him justice.