Global Water Cycle May Intensify Faster Than Thought

There is general consensus among scientists that in a warmer world, dry regions are predicted to get drier and wet regions are predicted to get wetter. However, a new study published in Science finds that this intensification of the global water cycle will occur at a rate double that predicted by current climate models. The researchers used observations of ocean surface salinity to determine which areas have become fresher and which areas have become saltier. They found that in a world 3.6 to 5.4 degrees F warmer than today—predicted to occur by 2100—the global water cycle will intensify by 16 to 24 percent. This is compared to approximately a 4-percent intensification over the last 50 years, during which time the earth warmed about one degree F. The more rapid change could significantly affect fresh water resources by changing the distribution of rainfall, and in turn, food security could become a serious concern.