Kathmandu – By the time the rain stops, Harvey will have dumped about 1 million gallons of water for every man, woman and child in southeastern Texas — a soggy, record-breaking glimpse of the wet and wild future that global warming could bring, scientists say.
While scientists are quick to say that climate change didn’t cause Harvey and that they haven’t determined yet whether the storm was made worse by global warming, they do note that warmer air and water mean wetter and possibly more intense hurricanes in the future.
There’s a scientifically accepted method for determining if some wild weather event has the fingerprints of man-made climate change, and it involves intricate calculations. Those could take weeks or months to complete, and then even longer to pass peer review.
In general, though, climate scientists agree that future storms will dump much more rain than the same size storms did in the past.
That’s because warmer air holds more water. With every degree Fahrenheit, the atmosphere can hold and then dump an additional 4 percent of water (7 percent for every degree Celsius), several scientists say.
Several studies show that the top 1 percent of the strongest downpours are already happening much more frequently. Also, calculations done Monday by MIT meteorology professor Kerry Emanuel show that the drenching received by Rockport, Texas, used to be maybe a once-in-1,800-years event for that city, but with warmer air holding more water and changes in storm steering currents since 2010, it is now a once-every-300-years event.
There’s a lot of debate among climate scientists over what role, if any, global warming may have played in causing Harvey to stall over Texas, which was a huge factor in the catastrophic flooding. If the hurricane had moved on like a normal storm, it wouldn’t have dumped as much rain in any one spot.
Harvey stalled because it is sandwiched between two high-pressure fronts that push it in opposite directions, and those fronts are stuck.
Sometime Tuesday or early Wednesday, parts of the Houston region will have broken the nearly 40-year-old U.S. record for the heaviest rainfall from a tropical system — 48 inches, set by Tropical Storm Amelia in 1978 in Texas, several meteorologists say.
Already 15 trillion gallons of rain have fallen on a large area, and an additional 5 trillion or 6 trillion gallons are forecast by the end of Wednesday, meteorologist Ryan Maue of WeatherBell Analytics calculates. That’s enough water to fill all the NFL and Division 1 college football stadiums more than 100 times over.
Source : Japan Times