Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Global Warming Surpassed Natural Cycles in Fueling 2005 Hurricane Season

26.06.2006
Global warming accounted for around half of the extra hurricane-fueling warmth in the waters of the tropical North Atlantic in 2005, while natural cycles were only a minor factor, according to a new analysis by Kevin Trenberth and Dennis Shea of the National Center for Atmospheric Research (NCAR). The study will appear in the June 27 issue of Geophysical Research Letters, published by the American Geophysical Union.

"The global warming influence provides a new background level that increases the risk of future enhancements in hurricane activity," Trenberth says. The research was supported by the National Science Foundation, NCAR's primary sponsor.

The study contradicts recent claims that natural cycles are responsible for the upturn in Atlantic hurricane activity since 1995. It also adds support to the premise that hurricane seasons will become more active as global temperatures rise. Last year produced a record 28 tropical storms and hurricanes in the Atlantic. Hurricanes Katrina, Rita, and Wilma all reached Category 5 strength.

Trenberth and Shea's research focuses on an increase in ocean temperatures. During much of last year's hurricane season, sea-surface temperatures across the tropical Atlantic between 10 and 20 degrees north, which is where many Atlantic hurricanes originate, were a record 1.7 degrees F above the 1901-1970 average. While researchers agree that the warming waters fueled hurricane intensity, they have been uncertain whether Atlantic waters have heated up because of a natural, decades-long cycle, or because of global warming.

By analyzing worldwide data on sea-surface temperatures (SSTs) since the early 20th century, Trenberth and Shea were able to calculate the causes of the increased temperatures in the tropical North Atlantic. Their calculations show that global warming explained about 0.8 degrees F of this rise. Aftereffects from the 2004-05 El Nino accounted for about 0.4 degrees F. The Atlantic multidecadal oscillation (AMO), a 60-to-80-year natural cycle in SSTs, explained less than 0.2 degrees F of the rise, according to Trenberth. The remainder is due to year-to-year variability in temperatures.

Previous studies have attributed the warming and cooling patterns of North Atlantic ocean temperatures in the 20th century—and associated hurricane activity—to the AMO. But Trenberth, suspecting that global warming was also playing a role, looked beyond the Atlantic to temperature patterns throughout Earth's tropical and midlatitude waters. He subtracted the global trend from the irregular Atlantic temperatures—in effect, separating global warming from the Atlantic natural cycle. The results show that the AMO is actually much weaker now than it was in the 1950s, when Atlantic hurricanes were also quite active. However, the AMO did contribute to the lull in hurricane activity from about 1970 to 1990 in the Atlantic.

Global warming does not guarantee that each year will set records for hurricanes, according to Trenberth. He notes that last year's activity was related to very favorable upper-level winds as well as the extremely warm SSTs. Each year will bring ups and downs in tropical Atlantic SSTs due to natural variations, such as the presence or absence of El Nino, says Trenberth. However, he adds, the long-term ocean warming should raise the baseline of hurricane activity.

Bob Henson | EurekAlert!
Further information:
http://www.ucar.edu

More articles from Earth Sciences:

nachricht NASA finds newly formed tropical storm lan over open waters
17.10.2017 | NASA/Goddard Space Flight Center

nachricht The melting ice makes the sea around Greenland less saline
16.10.2017 | Aarhus University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Ocean atmosphere rife with microbes

17.10.2017 | Life Sciences

Neutrons observe vitamin B6-dependent enzyme activity useful for drug development

17.10.2017 | Life Sciences

NASA finds newly formed tropical storm lan over open waters

17.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>