One of the biggest surprises to have come from studying the detailed environmental record from ice sheets and sediments, is just how quickly the world's climate can switch. Several times in the last few tens of thousands of years, the climate of large parts of the earth's surface has warmed or cooled by several degrees C over just a few decades. For example, the final warming and beginning of the meltback of the ice sheets around 11,500 years ago seems to have occurred mostly over about 70 years, and possibly much less (some indicators suggest most of the switch in climate occurred in less than 20 years). There are hints that dust fluxes may have had an important role in such sudden climate flips. High-resolution ice cores from Greenland show that in that region at least, dust fluxes from the continents switched slightly ahead of temperatures, over only about 20 years. The way that dust flux leads temperature tends to suggest that it played an important part in bringing about the sudden global climate switch. It may have acted as one of a number of amplifiers leading on from some triggering event that pushed the climate system into a different state. It is not hard to envisage how an initial warming or moistening of climate, perhaps just a random run of somewhat warmer or moister than average years, could lead to vegetation cover spreading and covering the surface. This could rapidly cut down the amount of dust blowing from the surface, and in a global climate system that is ripe for change the warming and increased rainfall could be picked up and amplified by other positive feedbacks. One important aspect of dust is that it can travel for thousands of miles, so the "signal" it sends out could rapidly affect many parts of the world simultaneously. The whole climate system would then have cascaded into a very different state, with vegetation cover effects on dust flux playing an important part in the change.
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