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Record Heat Means Hurricanes Gain Ferocity Faster
By Tim Radford
But Hurricane Harvey, which in 2017 assaulted the Gulf of Mexico and dumped unprecedented quantities of rain to cause devastating floods in Texas, happened because the waters of the Gulf were warmer than at any time on record. And they were warmer because of human-driven climate change, according to a second study.
Both studies examine the intricate machinery of a natural phenomenon, the tropical cyclone. Researchers from the Pacific Northwest National Laboratory looked at how fast four of 2017's hurricanes—Harvey, Irma, Jose and Maria—intensified: episodes in which maximum wind speed rose by at least 25 knots, which is more than 46 kilometers (approximately 29 miles), per hour within a 24-hour period. They report in Geophysical Research Letters that they combed through 30 years of satellite data from 1986 to 2015 to find a pattern.
Researchers have repeatedly warned that hurricane hazard must increase with global warming, driven by profligate human combustion of fossil fuels that dump greenhouse gases in the atmosphere. Hurricanes will hit higher latitudes and deliver more damage within the Gulf of Mexico. But climate change is only part of the answer.
The latest study did not find that storms were intensifying rapidly more often than usual. But the researchers did find that when a storm grew at speed, it became much more powerful within a 24-hour period than such storms did 30 years ago: wind speeds had gained 3.8 knots or seven kilometers (approximately 4.3 miles) an hour for each of the three decades.
And although hurricanes are driven by the warmth of the upper ocean, the researchers decided that rather than overall ocean warming, in this case the biggest factor was a natural cycle called the Atlantic Multidecadal Oscillation, which in its present phase tends to make ocean waters warmer in the central and eastern Atlantic—the spawning ground for Irma, Jose and Maria.
Warmest on Record
But when Harvey hammered the Texas coast in August 2017, the waters of the Gulf of Mexico were warmer than they had ever been. And scientists from the National Center for Atmospheric Research (NCAR) report in the journal Earth's Future that they calculated the rate of evaporation as the hurricane winds raced over the water and compared it with the levels of precipitation over the city of Houston.
To make a hurricane happen at all, ocean temperatures need to reach 26°C (approximately 79°F). When Harvey gathered its strength and its moisture, the Gulf waters had tipped 30°C.
"We show, for the first time, that the volume of rain over land corresponds to the amount of water evaporated from the unusually warm ocean," said Kevin Trenberth, a senior scientist with NCAR. "As climate change continues, we can expect more supercharged storms like Harvey."
Reposted with permission from our media associate Climate News Network.
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‘Companies Should Not Be Allowed to Use Hazardous Ingredients in Products People Use’: Michelle Pfeiffer Speaks Up for Safer Cosmetics
The beauty products we put on our skin can have important consequences for our health. Just this March, the U.S. Food and Drug Administration (FDA) warned that some Claire's cosmetics had tested positive for asbestos. But the FDA could only issue a warning, not a recall, because current law does not empower the agency to do so.
Michelle Pfeiffer wants to change that.
The actress and Environmental Working Group (EWG) board member was spotted on Capitol Hill Thursday lobbying lawmakers on behalf of a bill that would increase oversight of the cosmetics industry, The Washington Post reported.
By Julia Conley
Scientists at the United Nations' intergovernmental body focusing on biodiversity sounded alarms earlier this month with its report on the looming potential extinction of one million species — but few heard their calls, according to a German newspaper report.
The climate crisis is a major concern for American voters with nearly 40 percent reporting the issue will help determine how they cast their ballots in the upcoming 2020 presidential election, according to a report compiled by the Yale Program on Climate Change Communication.
Of more than 1,000 registered voters surveyed on global warming, climate and energy policies, as well as personal and collective action, 38 percent said that a candidate's position on climate change is "very important" when it comes to determining who will win their vote. Overall, democratic candidates are under more pressure to provide green solutions as part of their campaign promises with 64 percent of Democrat voters saying they prioritize the issue compared with just 34 percent of Independents and 12 percent of Republicans.
President Donald Trump has agreed to sign a $19.1 billion disaster relief bill that will help Americans still recovering from the flooding, hurricanes and wildfires that have devastated parts of the country in the past two years. Senate Republicans said they struck a deal with the president to approve the measure, despite the fact that it did not include the funding he wanted for the U.S.-Mexican border, CNN reported.
"The U.S. Senate has just approved a 19 Billion Dollar Disaster Relief Bill, with my total approval. Great!" the president tweeted Thursday.