Droughts Worse Than The 1930's Likely In The Twenty-First Century

The research, which will appear in the January 27th edition of Nature, proves for the first time that extreme fluctuations in the earth's water-resources during the last millennium occurred naturally in Eastern Africa. Mounting scientific evidence now suggests that large changes in climatic conditions have occurred across the globe over the last millennium and could reoccur independent of human-induced global-warming.

The existence of extreme, global climate changes provides a clue to the future, says Dr. Brian Cumming, a biologist with Queen's Paleoecological Environmental Assessment & Research Laboratory (PEARL). "Our research clearly indicates that we should be prepared for naturally-occurring, extreme climate changes that will provoke water shortages in the future," says Dr. Cumming, who co-authored the study with Queen's biologist Kathleen Laird and University of Ghent biologist Dirk Verschuren.

The research, which was conducted on Lake Naivasha in Kenya, shows that during the past 1,100 years extreme changes in water availability occurred many times in East Africa, sometimes producing major droughts lasting hundreds of years. The study mirrors previous studies in North America, the caribbean and Europe and confirms not only that extreme variations in climate exist, but that these large-scale weather patterns may have occurred on a global scale (like the medieval warm period from 1,000 to 1,200 AD).

Now intent on identifying the trigger for extreme climate shifts affecting water supplies in the past, the researchers speculate about the impact of current, human-induced global warming. "Our concern is that human industrialization could be a trigger for extreme climate changes on a global scale in the future, " Cumming says.

Researchers do know that if a global climate shift occurred - whether natural or human-induced - it would be overwhelming and could even precipitate large-scale migrations. The study reveals a direct correlation between scarce water-resources in Kenya during the last millennium and economic, political and social devastation.

Perhaps most alarming is the revelation that East Africa has enjoyed a relatively high level of water availability during the past 800 years (with three episodes of water shortages much more severe than the 1930's Dust Bowl). Consequently, development and population growth during the past centuries increased during the periods of abundant water resources. "So, if an extreme climate changes does occur in the future it could create widespread devastation," says Cumming.