Overestimating the cost of emissions reductions

Link to grist story here.

Video podcasts on climate change

Link to grist story here.

Have we oversold climate science?

Link to grist story here.

What does 'politicization of science' mean to you?

Link to grist story here.

Nature ends public peer-review trial

According to this story, Nature is scrapping its attempt to open up the peer review system.

As the article says,

In the Nature experiment, authors whose manuscripts were selected for traditional peer review could also opt to have them simultaneously posted on the Internet for feedback by rank-and-file scientists. Journal editors then weighed both sides when deciding whether a paper gets published.

The experiment generated high online traffic, about 5,600 page views a week, according to Nature. But it was ultimately canceled because few authors participated and many of the online comments were nothing more than "nice work."

My experience with open peer review (through the journal Atmospheric Chemistry and Physics) is similar. While it seems like a good idea, few articles get any public comments. I suspect this is true for a few reasons. First, it can be dangerous to make negative comments without anonymity (and on ACP comments must be attributed) --- which is why most journals implement anonymous reviewers. Second, it takes a lot of time to write a comment, and most people are simply too busy. Another reason the Nature experiment failed was that they did a terrible job publicizing it.

As a dedicated blogger, I see great value in an open comment system and I suspect that some kind of open system will eventually be adopted. However, I don't think any journal has yet stumbled upon the winning model.

New polling data on global warming ...

Link to grist story here.

Top 10 climate stories of 2006, part II

Link to grist story here.

Top 10 climate stories of 2006, part I

Link to grist story here.

Snowe and Rockefeller on the 'uncertainty' agenda

Link to grist story here.

The climate change insurgency

Link to grist story here.

The "uncertainty" agenda

Link to grist story here.

Why the Supreme Court case is not a really big deal

Link to grist story here.

Could the Sun be causing climate change?

Link to grist story here.

The CO2-temperature correlation

Hello, gentle readers. I'm back --- sort of. I've decided that I'm going to post on this blog links to my blog entries on grist.

I'm doing this because there's no way to get an RSS feed from grist for just my articles, and as a result it's easy to miss my posts. You can get an RSS feed from this page, and that will alert you to my new grist posts.

Also, some former readers have expressed some reticence about posting on grist. Feel free to post comments here or on grist.

My most recent post is on the well-known CO2-temperature correlation. You can find it here.

I'm going to Disney World!

OK, not really. Turns out I'm afraid of people in giant mouse suits.

But what IS happening is that this blog is moving to grist.org. Check out my blog page. Other than the host, everything else about the blog should remain the same. I hope you head over there and keep reading my stuff!

This web site will remain up, but I don't plan on posting here anymore.

[NOTE added in proof: the grist.org site requires an e-mail address to sign up. Here's a tip for those who don't want to give out their real e-mail: use the dodgeit.com e-mail avoider service. Check out their FAQ here. It's a great and free service that I use all the time.]

The "house of cards" analogy

In a comment to the "puzzle analogy" post, Bill Chameides points out an alternative analogy that climate skeptics like to push:

Science skeptics often try to undercut established science (be it global warming or something else) by portraying the knowledge-base as a house of cards. They hope by identifying one weak link, they can bring the whole house down (i.e., create the illusion of uncertainty in the entire subject.)

Examples of this strategy are easy to find. After the NRC hockey stick report concluded that we really don't know what the temperature was 1000 years ago, many skeptics used this to argue that this repudiated all climate science. This is, of course, nonsense. Important conclusions in science are all subject to multiple tests and verifications, and scientists do not accept a conclusion until it has been multiply verified. As Bill concluded:

In fact, most science is like a jigsaw - lots of interlocking pieces based on multiple, independent lines of inquiry. Even if you take away one piece, the picture is still apparent.

Canada's new greenhouse gas targets

A recent news article described a proposed greenhouse gas target for Canada:

Canada will aim to reduce its greenhouse gas emissions that cause global warming by 45-65 percent by 2050, ... The bill introduced Thursday in the House of Commons would also apply intensity-based targets until 2020, allowing emissions to continue to rise until then.

There're actually a lot of advantages of this target over something like Kyoto. First, it sets a definite long-term target, which Kyoto does not. This provides a more stable environment for people and companies to make investments in emissions reducing technology. Second, it allows emissions to grow in the near term, i.e., does not require sharp near-term cuts in emissions, as Kyoto does. Most economists agree that allowing some near-term growth followed by steeper cuts later provides the lowest cost trajectory to get to your preferred emissions level.

The downside of a longer term target is that it can be used as a stalling tactic if the administration really doesn't want to do anything about the problem. However, one need not wait long to find out if that's the case. While some emissions growth can be tolerated near-term, deviations from business-as-usual need to occur within a few years to hit the target in 2050 at minimum cost. Thus, if Canada is serious about this, we need to see some near-term actions relatively soon.

Finally, the target is not quite ambitious enough. In order to stabilize the climate at around 550 ppmv (i.e., double pre-industrial CO2), we need to reduce world emissions to about 2 GtC/yr, about 80% less than we're emittiong today. Their target, 45-65% reductions, would not be sufficient to do this if applied to the entire world.

Values in the climate change debate

An interesting editorial can be found here. One particularly interesting point they make is about the moral dimension to the problem:

Without mitigation, rising global temperatures are expected to cause ferocious hurricanes, tornadoes and floods; spawn heat waves, drought and famine; and prompt the spread of disease-carrying insects.

Middle- and upper-class families will hop in their cars to seek refuge from storms. They'll vaccinate their children and find good health care. They'll buy air conditioners. The poor, lacking resources to adapt, will disproportionately suffer and die.

Global warming isn't just an environmental debate. It's also about social and racial justice.

If you read the various blogs, many opposed to action will make the argument that addressing AGW is too economically damaging. My experience is that many of these people are so married to the economics of the problem that they don't even recognize that there exist different ways to look at the problem. In fact, the decision to take a cost-benefit view is itself a moral choices --- and one that is debatable.

My view is that some balance needs to be achieved: costs and benefits need to be considered, but so do the issues of social justice and fairness. Only by doing this can we obtain a socially and economically optimal solution to this problem.

The puzzle analogy

I recently heard a good analogy about climate science from Bill Chameides, chief scientist for Environmental Defense.

The state of science of climate change today is like a partially completed jigsaw puzzle. There are lots of pieces in place --- things we know quite well (like the water vapor feedback) --- and lots of areas where there are no pieces --- things we don't know particularly well (like cloud feedbacks). The point here is that you don't have to have every piece in place in order to know what the picture looks like. Consider the image above. While many pieces are missing, one can easily observe that it's an image of fruit.

Climate science is like that. While there's a lot we don't know, the big picture is still clear. We know the climate is warming, humans are contributing, and there's a risk of significant warming over the next century. The missing pieces don't change any of that.

The "uncertainty" argument would have you believe that, if even one piece is not in place, that we have no idea what the big picture is. That's simply not true.

Climate models vs weather models

You can find a lot of discussion on the net with arguments like:

If we cannot predict the weather next week, how can we predict the climate over the next century?

While this sounds like a reasonable argument, there are in fact good reasons to accept 100-year climate forecasts even though we cannot predict the weather more than a few days out.

Predicting the weather is hard because you have to get the exact details of a weather system right. If your prediction of a storm track is 100 km off, then a giant snowstorm predicted to bury a city might fall harmlessly offshore. If your temperature is 3 deg C off, then what you predicted as rain turns into snow. If your initial conditions are off, then precipitation predicted to fall during rush hour falls at midnight. All of these things mean that you've blown the forecast, and people will mumble about how weather forecasters don't know what they're doing.

For the climate, these things generally don't matter. What matters is that, in the long run, one gets the statistics of the weather right. If one storm in a climate model is 100 km too far East, that won't matter if the long-term statistics of the storm track is right. This is quite a different problem than predicting the EXACT evolution of a single atmospheric disturbance.

One simple way to think about the difference in predicting weather and climate is to think about rolling a six-sided die. Predicting the weather is like predicting what the next roll will be. Predicting the cliamte is like predicting what the average and standard deviation of 1000 rolls will be. The ability to predict the statistics of the next 1000 rolls does not hinge on the ability to predict the next roll. Thus, one should not dismiss climate forecasts simply because weather forecasts are only good for a few days.

One should not take from this that climate modeling is easier than weather forecasting. There are several aspects of the problem that make climate modeling more difficult than weather forecasting: climate models need to also predict the evolution of long time-constant domains like the oceans, cryosphere, and biosphere. Weather models don't have to worry about these things because oceans conditions, etc. don't change over a few weeks. Climate models also use uncertain predictions of future emissions, from which the atmospheric concentration of CO2 and other greenhouse gases will be determined.

Another statement you hear is that:

Because climate models do not predict next year's climate, why should you believe a prediction in 100 years?

Here's why: short-term forecasts (e.g., over the next few years) require accurate simulation of the magnitude and phase of short-term climate variability like El Nino. Over much longer time scales, however, one does not need to accurately simulate these short-term climate variability. I discussed that here. The upshot is again that one should not dismiss the long-term climate forecasts because short-term forecasts are problematic.