Timeblog.net

Today, as a special guest talk for my institute’s seminar, Paul Crutzen had been invited. He received the Nobel prize in Chemistry in 1995 for his work on discovering the mechanisms that lead to the destruction of ozone in the athmosphere.
He today talked about the influence humans have on our planet’s climate. He listed the numerous effects and causes that lead to drastical warming effects. He clearly stated that the raise in global average temperature of the last 20-30 years is only explainable by attributing it to anthropogenic (human caused) influences. While the amount of methane emissions seems to have stabilized, the important CO2-emissions have even increased. While a reduction by 60% would be needed, not even the industrialized countries manage to reach a reduction in emission levels (which they promised), and countries like China are only starting to emit.
So, as humanity doesn’t seem to be able to reduce CO2 levels he suggested another idea that might be able to stabilize the temperature level. He didn’t want to advocate this idea, just to throw it into discussion. The idea is to bring large amounts of sulfate into the stratosphere (1 Mt/year), and with the additional reflection this would lead to a cooling, that, in the very simple climate model it was tested in, would cancel out the warming by added CO2.
The idea is a bit offbeat, as it would require launching lots and lots of rockets each year to bring the sulfur up into the stratosphere. And even then, many more simulation would be needed to see if the wanted effects would be possible and if the negative effects were really neglectable. And of course, this just has “bad idea” written all over it, the kind of idea that sounds great (like getting lots of energy out of uranium nuclei) but has many negative side-effects. But, nevertheless, it is important to think and test such ideas, if only to show how desperate measures would have to be if we don’t sit down and finally start reducing CO2 emissions. (By the way, even this method would not prevent all negative effects from CO2, like the increase in acidity in oceans that will cause massive damage to ocean life.)