That would be interesting to look at. Do you have the data ? I looked around, but haven't been able to find a good graph for global drought frequencies.

Okay, we can play that game - proxy from China:

Strictly regional proxies don't count. Surely you know that.

And your pdf shows in section 2.5 that the Chinese MWP was cooler than today. So what should we make of that ?

And yes, some regions were warmer 1000 years ago, many other regions were not. The solution is to combine all data, and get a global view. Notice for instance, how some of the regional graphs show a peak at 900 AD, while others show a peak at 1100 AD. If you average them, both peaks will get smaller.

Fighting disinformation is not a crime.

Now, if anybody can present real evidence, that would be different.

Or conversely, what observations will falsify your hypothesis that human CO2 emissions will cause more dust bowls?

That's simple enough that you could prevent the rhetoric and just fill in the answer yourself.

Plot a graph for the number of droughts in the next 50 years, and if you don't see any significant increase, CO2 emissions are not a factor.

Now what ?

variations or no, the levels should still have risen over the last couple of years

That makes no sense. Ocean level data is very noisy. You cannot expect to see a trend in a small amount of noisy data, even if it's still there.

There are plenty of temperature reconstructions based on different kinds of proxies. Every colored line in the graph I posted is based on such a proxy.

Unfortunately, those proxies are all we have, but they are in general agreement that the MWP was cooler than today.

In order to show MWP was warmer, you'd have to find a suitable proxy, with small enough error bars. Preferably you'd show a combination of different ones, all in agreement.

In any case, absent any further evidence, claiming that the MWP was warmer than today is silly.

The increase in CO2 is not natural, and it's not by definition irreversible.

Warning that we're about to go over the 450 ppm level isn't over hyped doomsday rhetoric. It's just simple extrapolation of current trend.

We can still argue whether 450 ppm is the correct upper limit, and scientific discussion is still ongoing. The question is: while the discussion is still going on, should we go ahead and exceed the 450 ppm level, knowing that we don't really have a way to extract the CO2 from the atmosphere if we're wrong.

There's a theory that global warming lead to anoxic oceans, which led to hydrogen sulfide emissions, killing most life on the planet.

Of course, there's no solid evidence that this was the cause for the extinction, but it's a fairly good candidate.

On the other hand, there's also no solid evidence that continuing our path of CO2 emissions is not going to cause damage.

Yes, every change means that someone will profit. But at the same time, everybody else will lose.

Unless the government is corrupt, they'll try to look out for the economy as a whole.

Actually, most scientists agree it's much warmer now than during the MWP.

Here are the modern temperature reconstructions for the last 1000 years.

https://secure.wikimedia.org/wikipedia/en/wiki/File:1000_Year_Temperature_Comparison.png

If you have solid evidence that the WMP was globally warmer than today, I'd love to see it.

Even though weather is not climate, the large amount of broken weather records is certainly an indication that the climate is shifting.

There's is evidence this has happened before in the end-Permian extinction.

Honestly, do you want to give the green light to scientists to do experiments with our one and only fragile global climatic system?

Urmm.. that's exactly what we've been doing for the last 100 years.

What you're stating is the broken window fallacy.

https://secure.wikimedia.org/wikipedia/en/wiki/Parable_of_the_broken_window

All those things are bad for the economy, which is the reason that the governments haven't actually done anything so far.

PLANT LIFE ON EARTH DEPENDS ON IT.

True but irrelevant. It's like saying it's okay to flood cities with water, because fish depend on it.