[TriinT]

Krugman is a dismal scientist (a.k.a. economist), not a real scientist. His pedantry and demagogy are too much to bear. He can't even predict the effects of economic policy and now he's trying to predict the weather? What next?

Contrary to popular belief, the ice caps are not shriking all the time. Sure, they were shrinking really fast some years ago, and everyone went hysterical because of the rising sea levels and drowning polar bears. But when the ice caps started growing again, no one said a thing. If that isn't cherry-picking, I don't know what is.

[quoderat]

Your data is wrong. Did you even bother to check?

http://www.nasa.gov/topics/earth/features/arctic_thinice.htm...

"Until recently, the majority of Arctic sea ice survived at least one summer and often several. But things have changed dramatically, according to a team of University of Colorado, Boulder, scientists led by Charles Fowler. Thin seasonal ice -- ice that melts and re-freezes every year -- makes up about 70 percent of the Arctic sea ice in wintertime, up from 40 to 50 percent in the 1980s and 1990s. Thicker ice, which survives two or more years, now comprises just 10 percent of wintertime ice cover, down from 30 to 40 percent.

According to researchers from the National Snow and Ice Data Center in Boulder, Colo., the maximum sea ice extent for 2008-09, reached on Feb. 28, was 5.85 million square miles. That is 278,000 square miles less than the average extent for 1979 to 2000."

And yep, parts (but only parts) of the Antarctic ice cap are growing -- but guess why? Warmer air creating more snowfall.

You people are hopeless. Data, facts, evidence -- none of it sways you. It's like some religion.

[mlinsey]

I'm not a climate scientist (though a big problem with this issue is it requires lots of non-climate scientists to formulate opinions about climate science), but this post definitely doesn't deserve to be downvoted for linking scientific research, even with the commentary in the last paragraph.

[bokonist]

Total sea ice is as high as ever: 'On a global basis, world sea ice in April 2008 reached levels that were "unprecedented" for the month of April in over 25 years.' source: http://www.climateaudit.org/?p=3066

Could warming have caused ice to melt in the northern hemisphere and grow in the Antartic? It's possible, but the explanation starts smelling like a "just so story". The explanation by NASA that the loss of Artic Ice is caused by cyclical changes in global wind patterns seems to better fit the facts. (see http://www.nasa.gov/vision/earth/lookingatearth/quikscat-200... and http://wattsupwiththat.com/2007/10/03/nh-sea-ice-loss-its-th... )

You people are hopeless. Data, facts, evidence -- none of it sways you. It's like some religion.

Please, let's stop with the personal attacks.

[quoderat]

The problem is, increasing Antarctic ice is expected, given the warming actually occurring:

http://dotearth.blogs.nytimes.com/2008/06/27/whats-really-up...

"But scientists studying trends at both poles say there is nothing inconsistent with the intensifying greenhouse effect. William Chapman, who maintains the helpful Cryosphere Today Web site at the University of Illinois, Urbana-Champaign, sent me an email this morning reminding me of a 2005 study that projects more Antarctic sea ice (by volume) in a warming world."

And that's without even getting into the question of is the climate change anthropogenic or not. Given what we know about CO2, hard to see how it could be otherwise, but not worth arguing over. What will happen, will happen.

[bokonist]

The study you cite is neither predictive nor evidence based. It is a speculative, after the fact explanation: "We used computer-generated simulations to get this research result. I hope that in the future we'll be able to verify this result with real data through a long-term ice thickness measurement campaign." ( http://www.sciencedaily.com/releases/2005/06/050630064726.ht... )

That doesn't mean it's necessarily wrong. But it is not evidence, nor is it conclusive. There is simply no reason to believe Powell's explanation over the explanation I cited in my previous comment. The NASA explanation is based on actual observation rather than computer simulations.

The climate is so complex that you can always come up with an after the fact explanation. The only way to judge science is either a) by the predictions it makes or b) following the chain of deductive reasoning. Predictions are not really possible with climate science in the short term because there are too many variables. So that leaves b). I have not studied the science behind sea ice changes closely. But many of the global climate models have been subjected to egregious tuning: http://www.climateaudit.org/?p=2475

Given what we know about CO2, hard to see how it could be otherwise, but not worth arguing over.

The effect of CO2 on temperature is both a) logarithmic and b) non-cumulative. For models to predict a levels of warming that are actually alarming, the models must include feedback loops. No one knows if these feedback effects are real. They are entirely speculative.

[TriinT]

Funny, but the data I had told a rather different story. Gonna look for the URLs to back it up and I will be right back.

"None of it sways you" -> please spare me of your attacks. They don't add anything to the discussion and they only weaken your point.

[mlinsey]

Why are your attacks on Krugman more constructive than the GP's attacks on you? Because Krugman isn't posting here?

[TriinT]

Because Krugman is intellectually dishonest and because he's a public figure. His opinions shape the thoughts of the population. Nobody reads my opinions. Thank goodness I am no public figure.

If you're going to address the public, you should be honest. Krugman is an economist. He constantly sells half-baked, hand-waving arguments as absolute truths. And this is not because he's a "liberal". The same happens with all the "conservative" economists who also write dishonest articles.

Economics is hard. Very hard. An "expert" who tells the public he does not know will be frowned upon. But that's the point: experts don't know everything, and should not claim to know more than they do.

Greenspan himself wrote that when he ran the Fed sometimes they were completely "lost" and made decisions based more on gut-feeling than solid economic theory. Greenspan is pretty much retired now, so he can afford to be frank. Krugman still has a career, so he can't afford that.

[bokonist]

Public figures are almost never intellectually honest, because in order to get to their position they usually have to align politically with either the Left or the Right. Facts and arguments are not methods for discovering truth but weapons for assaulting the other team.

At Hacker News we hold everyone to a higher standard. We are not trying to influence policy but to seek truth. We do not want the site to degenerate into the NYTimes or Wall St. journal editorial page.

[DanielBMarkham]

An "expert" who tells the public he does not know will be frowned upon. But that's the point: experts don't know everything, and should not claim to know more than they do.

This is the tension in science. You take all of that schooling, and for what? To admit you're as stumped as everybody else?

I mean seriously, when is the last time you saw a science show where they basically said "Beats me"? Instead it's all upbeat and glossed over.

The way we sell science and actual state of science are two completely different things.

[TriinT]

Science shows are entertainment, mostly. Their goal is to promote Science, and I think they do their job well.

I have had the priviledge of working with some truly top-notch scientists. A common trait among them is how honest they were on the limitations of their knowledge. They were not afraid to say they were wrong, or that they didn't know.

This was in their academic environment. I don't know if they would be that honest when addressing the public. The average person would probably not be able to understand how's it possible that an illustrious professor has spent his entire career studying elementary particles and is still baffled by them. That is due to the fact that the average person does not know what deep knowledge is, and does not need to know.

[quoderat]

If my point is correct, and the evidence, facts and data all align with it, then anything else I say is irrelevant.

That's the problem, though -- people make these decisions based on emotions, vested interests, or what they wish were so, rather than the real evidence. If global warming/climate change is harmful to capitalist greed (and I don't think all capitalism is greed, or vice versa), then it prima facie must be incorrect, in some folks' view.

Not saying you are guilty of that, but so very many are.

[TriinT]

Suppose the weather is indeed changing. It does not matter whether this is caused by man or not. And one does not need to wait to have irrefutable evidence to start acting.

People build computer models to simulate the weather. The physics is not the problem. The initial conditions and the assumptions are the problem. The atmosphere is vast. We can measure temperature and other stuff mostly at the Earth's surface. Some people are now building UAVs to fly around and collect measurements which will be used to increase the accuracy of the climate models. One problem: the climate is a chaotic system, i.e., it's highly sensitive to disturbances on initial conditions. Another problem: the models neglect the biosphere. Most carbon is in the biosphere, not in the atmosphere. Computer model says temperatures are going to increase 9 degrees Celsius. People panic. Wait. Does anyone know how to model the dynamics of the biosphere?! Short answer: no. It's a complicated problem. You can forecast CO2 emissions from industry, but no one has a clue how the biosphere will react to abrupt temperature variations.

One caveat: there are cycles. The Sun has cycles. The Earth also has cycles. The temperature in the middle ages was known to be a few degrees higher. Was it also due to CO2 emissions from the industry? Definitely not.

There was a time when there was no ice on the Arctic. There was also a time when most coastal areas we have today were underwater. There's no reason why that can't happen again, for sure.

An important issue: what does "global warming" even mean? Are the minimum / median / average / maximum temperatures increasing? Or is the variance increasing? Does this happen everywhere. What I read was that the cold, high-latitude regions were getting "warmer" (whatever that means), while the tropical regions were pretty much the same. This is too much complexity to be sold to the masses. The masses want entertainment, not information.

OK, suppose that temperature will increase by 9 degrees or so. Sea levels will rise and threaten us all. The U.S. can try to regulate emissions to counter this, but will the Chinese do the same? This is Game Theory 101. Moreover, what will people in the U.S. and Europe say:

"Sorry you Chinese, Indians and Brazilians. We destroyed the planet, and now we won't allow you to develop because of that. If you want to keep your houses warm in the winter and power your industry, we will accuse you of treason."

Last but not least: is regulation the best solution? What is the problem with global warming exactly? Rising sea levels? Increased CO2 concentration is good for the plants because they grow faster. I say, build a pipeline from the Arctic to the Sahara to pump fresh water into local agriculture. If the Israelis can grow tomatoes in the Negev desert, I don't see why the North Africans can't do the same.

The problem with regulation is that it won't work on a global scale. A politician would rather compromise the planet than tell his own people that they have to starve and freeze to reduce emissions. This is much more than capitalist greed. This is about human rights: people should have the right to consume energy to increase their standard of living.

Science is one thing. Policy is another. Let us keep them separate. Studying the climate should be decoupled from politics as much as possible.

[dantheman]

Don't forget chaos theory and rounding errors. Chaos theory was initially discovered when by running a weather simulation with the same inputs and recieving different outputs due to floating point rounding errors.