A new study by a diverse group of researchers from twelve countries found that of the human impacts stemming from climate change, the threat it poses to global water supplies may be the most severe. Published in the Proceedings of the National Academy of Sciences and reported in the journal Nature, the researchers found that if global temperatures rise by an average of 2°C, up to a fifth of the global population will suffer from severe water shortages.

"The multi-model assessment suggests that, in vulnerable regions, climate change will significantly add to the problem of water scarcity that is already arising from population growth," Nature reported. "The modellers found that climate-driven changes in evaporation, precipitation and run-off will result in a 40 percent increase in the number of people worldwide who must make do with less than 500 cubic meters of water per year - a commonly used threshold to signify 'absolute' water scarcity."

The findings show that the regions most at risk from water scarcity include parts of the southern U.S., the Mediterranean and the Middle East.

Prolonged drought is already taking its toll on several U.S. states. 2013 was the driest year on record for much of California, with both Los Angeles and San Francisco setting low precipitation records that hadn't been met since official record-keeping began in the mid-19th century. Overall, 2013 ended with about 31 percent of the contiguous United States experiencing moderate or extreme drought, according to the U.S. Drought Monitor.

Metalworking Fluid users, manufacturers and sellers have a big task ahead. Some companies like FORD, are seriously researching dry machining, but that's not enough. As the system works, the cost of water may determine the right products, process and equipments to save every drop. Original Article from nature.com.