Warm waters boosted major hurricane tally
Extra whopper storms
WASHINGTON, Sept 30, (AP): The Atlantic’s warmer waters triggered the unusual number of major hurricanes last year, according to a new study that predicts the region could see a couple of extra whopper storms each year by the end of the century.
Six major hurricanes – with winds of at least 111 mph (178 kph) – spun around the Atlantic last year, including Harvey, Irma and Maria which hit parts of the United States and the Caribbean. Since 2000, the Atlantic has averaged three major hurricanes a year. Before that the average was closer to two.
It may go up to five to eight major hurricanes a year around the year 2100, according to a study in Thursday’s journal Science.
“We will see more active hurricane seasons like 2017 in the future,” said lead author Hiro Murakami, climate scientist and hurricane expert at the National Oceanic and Atmospheric Administration.
So far this year, though, only one Atlantic hurricane, Florence, has reached major status.
Warm water acts as fuel for hurricanes. Water has to be at least 79 degrees (26ºC) for a storm to form. The warmer the water, the more it can resist forces that would cause it to weaken, said University of Miami hurricane researcher Brian McNoldy, who wasn’t part of the study.
McNoldy
Conditions
Murakami found that a combination of natural conditions and man-made climate change made the waters warmer in one key area, which caused more major storms. That area is essentially a large box from south of Florida and north of South America, stretching all the way east to Africa.
Some of the strongest Atlantic hurricanes form off the coast of West Africa, then chug west toward the Caribbean and the US East Coast.
Water in that large box – the main hurricane development region – averaged 0.7 degrees (0.4ºC) warmer than normal for the entire 2017 season, which is unusual for a six-month time period, Murakami said.
Murakami’s study used computer simulations to isolate different climate conditions. Although his research showed both natural and human-triggered causes from the burning of coal, oil and gas, Murakami said he couldn’t separate them enough to see which was bigger.
He used the computer models to look into the future. The Atlantic is projected to warm faster than the rest of the world’s oceans. That difference is why Murakami said the number of major storms will probably increase by two or more on average.
Some outside experts had issues with parts of Murakami’s study.
McNoldy said it makes sense that the unusual warm water was to blame in 2017, but he wasn’t quite ready to point the finger at global warming.
“Hurricane seasons don’t just keep getting more active as the climate warms though. There is enormous variability,” McNoldy said in an email.
Kevin Trenberth of the National Center for Atmospheric Research faulted Murakami’s study for not taking into account the large increase in ocean heat in deeper areas, which he said is also due to climate change.
Princeton University’s Gabriel Vecchi said some computer simulations don’t show the Atlantic warming fastest, so it’s not quite as certain that there will be more major storms there in the future.
On the map, their homes are tiny specks in a vast sea of blue, rarely in the headlines and far removed from the centers of power. But for a few days each year, the leaders of small island nations share a podium with presidents and prime ministers from the world’s most powerful nations, and their message is clear: Global warming is already changing our lives, and it will change yours too.
Speaking shortly after US President Donald Trump – whose fiery speech made no mention of climate change – Danny Faure told the UN General Assembly this week that for his country, the Seychelles, it’s already a daily reality.
Unpredictable
“We see its effects in our eroding coastlines and unpredictable weather patterns,” he said. “We see its effects on our coral reefs and rising sea levels.”
The Indian Ocean nation off the east coast of Africa is one of dozens of Small Island Developing States – or SIDS for short – that have been trying to draw attention to what they see as the overarching threat of our time.
“Decades ago, small island developing states warned the world of the risks of climate change, and those were once theoretical threats,” said Hilda Heine, president of the Marshall Islands, a sprawling series of atolls in the Pacific Ocean thousands of miles north of Australia.
The message may finally be getting through, in part due to the devastating wildfires, storms and floods that have affected millions of people in the developed world over the past months.
“The extreme weather events lately have underscored to leaders elsewhere that this will affect their populations, too, in the here and now,” said Alden Meyer of the Union of Concerned Scientists, who has followed international climate negotiations for many years.
The realization may help push leaders to commit to greater action to rein in climate change ahead of a year-end deadline that countries have set themselves to flesh out the 2015 Paris climate accord, Meyer said. But he warned that there remains a big gap between the rhetoric on climate change, and the willingness of leaders of major economies like Germany or Japan to take decisive actions, such as stop burning fossil fuels.
Despite its minuscule carbon emissions, Heine said her nation wants to show it, too, is prepared to do its part. The country is aiming to achieve net zero emissions by 2050, a goal most climate experts consider an absolute deadline if the world is to avert runaway warming of more than 2ºC (3.6ºF) by the end of the century.
Marshall Islanders know the future of their country, much of which is little over a meter (3.3 feet) above sea level, hangs in the balance. A recent report predicted that the world’s oceans will rise by an average of at least 2 feet (61 centimeters) by the end of the century compared to now. Experts say the actions of the United States, which Trump announced will pull out of the Paris agreement, could play a decisive role in the future of small islands.