We have all heard about the Ice Age, if only in cartoon movies. A time when massive ice sheets covered the planet while mammoths and saber toothed cats roamed the frozen landscape. What is more, the cycle of interglacial-glacial-interglacial has happened over and over again during the past million or so years. During the last half a million years the cycle has repeated every 130,000 years, with the warm period we are now enjoying—the Holocene—just the latest interglacial respite from the icy conditions of the Pleistocene Ice Age. What most people don't know is that there were many areas on Earth that remained unchanged, even during the height of the last glacial period. The Sahara was hot and dry, and in the Amazon rainforests, though a bit smaller in area, looked much like they do today.
Chad, located along the southern edge of the Sahara Desert, is the dustiest place on Earth. Recognizing that aerosols plays a vital role in climate and biophysical feedback in Earth's environmental system, climate researchers are turning to dust as a major driver of climate change. A new article, to be published in PNAS, identifies the Bodélé Depression in Chad as the producer of about half the mineral aerosols emitted from the Sahara. According to Richard Washington et al. dust could be a “tipping element” where “small features of the atmospheric circulation, such as the Bodélé Low-Level Jet, could profoundly alter the behavior of this feature.” With the impact of CO2 diminished due to a cooling climate climate, researchers are searching for new hazards: Is African dust the new carbon dioxide?