Megadroughts, dry periods which can last up to 35 years, don’t happen often, but there is ample evidence that they’ve occurred in the American Southwest between 1300 and 100 BCE. We also know that major droughts, whether megadroughts or not, have destroyed several ancient civilizations.
Drought is something to take very seriously because recent a recent study led by Cornell University suggests that the chances of such a megadrought striking in the American Southwest will increase significantly over the course of this century.
As the average temperature around the Earth goes up, soil will have a harder time holding on to moisture, and the way water is balanced between soil, plants, and the surface will change. In places like the Southwest, which are already dry, this could be disastrous.
If global temperatures go up by 2 degrees Celsius over the next century, it will increase the chances of a Southwest megadrought over the next century by 20 to 50 percent. If they hit 4 degrees Celsius, that chance increase to 70 to 99 percent.
While “over the next century” may not seem too soon, bear in mind that the year 2100 is part of that century, as are the 34 years after it, and you could well have family members who live through it.
There is still hope, though. If scientists can develop a system to drastically cut greenhouse gases, something that a lot of researchers around the country are already trying to do, we can prevent the temperature from rising that much and keep the chances of a megadrought closer to what they are, which, while it isn’t 0 percent, it is a lot less likely.
“I wouldn’t ever bet against our ability to, under pressure, come up with solutions and ideas for surmounting these challenges, said study co-author Jason Smerdon of Columbia University, “but the sooner we take this seriously and start planning for it, the more options we will have and the fewer serious risks we’ll face.”