To say it's simpler is usually an attempt to explain the matter to laypersons, and also to counter the view that climate simulation should be necessarily harder than weather simulation.

One reason I personally think that climate is "easier" is that a realistic result, not too far from evidence or current state-of-the-art climate models, can be calculated by pen and paper doing analytical math about the greenhouse effect. Estimates of the possible impact of CO2 pollution have not changed very much in 100 years.

Of course the level of complexity of current research is exactly where the capabilities of scientists dictate, and this limit is pretty much the same for weather and climate ;-).

For the number I found, they specifically said this is not the atmospheric lifetime of any single CO2 molecule (which would be shorter), but rather the duration of disturbance caused in total CO2 levels (and as such is the number we're interested in). For SO2, I didn't find a site being this specific, but as SO2 readily transforms into sulfuric acid in the atmosphere (and behaving as it does otherwise), I suspect CO2 has much more opportunities for feedbacks and everything.

In any case, burning fossil fuels - essentially digging up carbon-containing rocks and fluids from underground, and freeing the carbon into the atmosphere in CO2 - will increase the amount of carbon atoms in the circulation (atmospheric CO2 -> plant -> animal -> animal -> atmosphere and other cycles). These carbon atoms do not leave the circulation easily. Mainly by accumulation of organic material in swamps and on ocean floors, I think.

Image-googling for "historical co2 levels", one finds graphs that suggest that when CO2 levels go down, they go down at a steadyish pace of 20 ppm per million years. So maybe this is near the actual speed of accumulation of carbon? That's a guesstimate tho.

WOAH! Which religion did that just come from?

Right, it has been covered by ice periodically in recent times. But only in recent millennia when there hasn't been much CO2 in the atmosphere. There have been very long periods without significant glaciation on Earth. CO2 levels are already much higher than ever before during recent glaciation events, and we might very well be in for another 250 million years without ice.

That's the key, see. Our emissions have already pushed the climate system of Earth beyond the boundaries of what it has been during the last few millions of years. The current ice age started 2.6 million years ago (with alternating glacials and interglacials), and it might be over in 1000 years. Before the current ice age there was 250 million years without glacial periods.

When evidence doesn't fit the model, *fix* *the* *model*. The scientists have fixed the model, but still you're not happy!! The problem of their model: underestimation of sulfuric acid emissions from China. The new study shows that a model with more realistic SO2 pollution gives more realistic predictions. The scientists have not come up with an excuse, they have shown beyond reasonable doubt that Chinese SO2 emissions are *expected* to cause evidence to be what we see.

Parent is Sad, not funny. However can't rate it as such :(.

How anyone could not see that the last decade was warmer than previous decades is beyond me. Also it's rather evident from the data that between 2000 - 2010 there was not a strong trend.

Grand claims are needed (if you're referring to the claim "anthropogenic air pollution very probably results in significant warming of Earth's climate", which is pretty much the biggest claim scientists made). There's a reason to think that way, and that reason has been questioned by tens of thousands of capable minds over the course of decades. Intelligent humans would listen to the warning, and act even when the above is not completely certain. Nothing can ever be completely certain, but scientific results will always be the closest thing.

By the way, we *are* able to predict the weather to a known level of accuracy, which is also rather high for short-term forecasts. Climate simulation is the same thing but much simpler (because we don't care about where and when it will be what temperature, only the average), but of course more difficult because of other reasons. That said, there are many uncertainties, some so uncertain that no value is given, but their range *is* known. The possible ranges can be read in the IPCC documents from 2007. This-and-that effect cannot be bigger than some limit, and these values are quite trustworthy, because if some effect was HUGE, then it would necessarily also be evident. The sun's impact is actually pretty well known - the changes in power output have been much too small to account for detected changes.

The temperature measurement network isn't grand, but it's also not giving out random numbers. We know that. The numbers don't look random. The signal-to-noise ratio is big enough that we can use those numbers, and other effects are accounted for (right, some thermometers are next to asphalt, but guess what - asphalt warms up the ground, there's now more asphalt than 50 years ago, thus asphalt indeed contributes to global warming (I suppose these effects go under the label of "land use" in IPCC documents if you want to look it up)).

Scientists are sceptics and continue to be that. But this means more than just questioning findings. Turns out the scientists have long ago researched the problem of how good their results are, and the 2007 report was groundbreaking indeed because then, for the first time ever, scientists concluded their results are "very probably correct". And mind you, their result was that the humans cause warming in the range of 0.6 - 2.4 watts per square meter. Of course there's always a tradeoff between dependability and accuracy of some result, now the numbers add up such that scientists can very confidently say something that's very approximate, but still useful.

By the way, the biggest uncertainty in climate forecasts is the amount of pollution humans spew out in the future. How would they know that? They wouldn't. We might be able to cut pollution by 50% in 20 years, or we might quadruple it in the same time frame. No way to know.

Well, the matter will become important with time. It goes like this: atmospheric lifetime for CO2 is estimated to be thousands of years, while numbers elsewhere on the web say this time is a few days for sulfur dioxide. That means that if, before humans, a volcano erupted releasing both CO2 and SO2, the SO2 levels would return to normal within days to weeks afterwards, but CO2 levels would remain elevated for thousands of years.

So, if one starts a new coal plant without scrubbers and thus introduces a steady flux of CO2 and SO2, the resulting increase in the SO2 level will stabilize within weeks, but CO2 level in the atmosphere will continue rising for as long as the plant operates. Thus, starting a new plant actually cools the climate at first, but eventually the CO2 emissions catch up and flip the balance. No scrubbers needed, although they can get rid of the cooling effect (and acid rain).

This sounds like a very plausible reason (amongst other things) why the last 10 years didn't see a strong trend of temperature increase.

Winter is not a problem for a large part of Earth's urban areas, and by what googling I could manage, Taiwan seems to be one of the luckier sites (although some sites say that the north part has seasonal variability). The deciduous trees could be wrapped up with led strings in the winter - this is what we do for christmas anyway - and there'd still be savings half of the year.

Also. Trees producing golden light! O Laurelin, o Telperion! It's the stuff of legends!

That has also happened in non-digital social networks, no?

There's nothing wrong in that people can be arrested or detained based on information received from other people. Internet is not some detached thing we shouldn't take seriously - it's a part of Real Life(tm) and must be dealt with an approppriate level of seriousness.

Right, but if you don't modify it, just use and distribute? Isn't that what ubuntu is doing? So what's the criticism about in the original article?

Actually the latest IPCC report contains a very conservative estimate for the melting of Greenland ice sheet. This is because that melting is (and was) not known well enough to make good estimates. Likewise for Antarctica. More specifically, the 2007 report contains numbers for melting between 1993 and 2003.

The linked article talks about 230 GT of ice annually from Greenland and 132 GT from west Antarctica. This rate is supposedly from the last two years (2008-2010 presumably), and adds to 3 mm / year sea level rise. Halving that means 1.5 mm / year from these two sources. The IPCC report contains the number of 0.42 mm from these sources combined.

The IPCC prediction is a bit on the low side (only 30-50 cm per century) because of this. They're underestimating, and they know it and say so. Of course there are newer bigger numbers for melting for both Greenland and Antarctica, but as these numbers vary this much between studies, IPCC shouldn't (and doesn't) include them in their great scenarios.

Just a reminder - sea level rise does not need ice sheet melting. A good sea level rise can come from thermal expansion alone. The IPCC report for policymakers says that less than 10% of observed sea level rise is thought to result from Greenland melting.

That's what I thought. Heck, build large triple windows and use curtains on hot summer days?

Another thing of wonder was heating by gas. Why not use a heat pump to turn their own solar electricity into hot water to circulate under their floors? Burning a fossil fuel for heat is not green (although I guess it could be bio-gas, but that stuff has so many other uses that it's better to save it).

Clothes dryers make no sense. Clothes dry very well on their own when hanged on a string. Also most of the time vacuum cleaners don't make sense, a good broom does the same job just as easily (with some exceptions).

Exactly. That's what I found most disappointing about 3D. Normally I've been looking at the scenery too, but I think this wonderland movie was much more mushy than stuff in 2d movies ever is.