Summary
| Subject keyword(s) | Atmospheric science, Climate, Climatology, Earth and space science, Geoscience, Global climate change, Hurricanes, Weather |
|---|---|
| Grade level | Middle School, High School, Higher Education, Informal Education |
| Intended audience | Learner |
| Resource type | Reference Material |
| Resource format | text, text/html |
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Support provided by Ancient Worlds Body + Brain Evolution Military + Espionage Nature Physics + Math Planet Earth Space + Flight Tech + Engineering Print Share A A A Stronger Hurricanes Is global warming making hurricanes more intense? Aired January 10, 2006 on PBS Posted 01.10.06 NOVA scienceNOW Watch Stronger Hurricanes 06:00 Aired January 10, 2006 on PBS Program Description Are hurricanes becoming more intense? As M.I.T. atmospheric scientist Kerry Emanuel relates in this video, over the past half century the average strength and duration of hurricanes in the tropical regions of both the Atlantic and Pacific oceans has doubled. Sea surface temperatures have also been on the rise, likely exacerbating the situation. Will this sobering trend continue? Transcript STRONGER HURRICANES PBS Airdate: January 10, 2006 After Hurricane Katrina a lot of folks were thinking about our planet andwere asking, "Are killer storms on Earth becoming more frequent? And if theyare, why?" We've always known that hurricanes on our planet come in cycles, butreporter Chad Cohen looked back at the past season and wondered if maybethere's something else going on here. CHAD COHEN (Correspondent): You're looking into the eyeof the most intense Atlantic storm ever measured. It's not Katrina, thehurricane that devastated New Orleans. It's Wilma, the third Category 5 stormto form in the Atlantic in the 2005 season. Wilma set a new record, suggestingthat more intense hurricanes may be in store. And if there's a reason why, it's out here. Research ships like this one,run by N.O.A.A., take the ocean's temperature every three hours, 24 hours aday. As the crew reels in this elaborate probe, they bring back evidence thatthe oceans are heating up. These numbers have presented us with one inescapable fact, the surfacetemperatures of the world's oceans has gone up a half degree Celsius in justthe last 35 years. And there's nothing hurricanes like more than warm water.The more warm seawater a storm can churn into vapor, the more heat is releasedinto the upper atmosphere. That lowers the pressure and causes winds at theocean surface to spiral inward and pick up speed. And some scientists, likeM.I.T. atmospherics professor Kerry Emanuel, believe that the rise in oceantemperatures is the result of global warming, the heating of the Earth causedby human activity. Can we say for sure that we're causing that warming? KERRY EMANUEL (Massachusetts Institute of Technology): The lastfew decades, the temperature has gone up so quickly and so far out of whatwe've seen in the last thousand years or so, that virtually everybody in thebusiness now believes we're seeing a manmade signal in the globaltemperatures. CHAD COHEN: And we know that hurricanes like warm water. Soit's very easy to just kind of say, "There it is. We're causinghurricanes." KERRY EMANUEL: We can't say we're causing more hurricanes. CHAD COHEN: We can't say we're causing more hurricanes,because the total number of hurricanes worldwide hasn't changed at all. Forreasons no one can explain, it always seems to hover right around 90 per year.So if global warming hasn't caused more hurricanes, has it made themstronger? To find out, Kerry Emanuel took advantage of five decades worth of datacollected by aircraft flying directly into the paths of hurricanes. Heconcluded that over this time, the average strength and duration of hurricanesin the tropical regions of both the Atlantic and Pacific oceans has doubled.But even more sobering is how closely this increase in storm power matches therise in ocean temperature. It's pretty striking, actually. You look at the graph and the sea surfacetemperatures go up like this, and the intensity of hurricanes goes up, itfollows perfectly. KERRY EMANUEL: Yes, that's right. I think you can say, fairlyunequivocally, that half a degree rise in ocean temperature will causehurricanes to be more intense. PETER WEBSTER (Georgia Institute of Technology): This is theequator, here. CHAD COHEN: At Georgia Tech, Peter Webster examined acompletely different set of hurricane measurements, 30 years of globalsatellite observations. His conclusions mirror those of Kerry Emanuel's. PETER WEBSTER: We find a consistency between the increase of surfacetemperature in all of the oceans and a change in intensity to more intensestorms. CHAD COHEN: But while both scientists agree that warmer oceanshave contributed to more intense storms, they caution that formation ofhurricanes is complex, to say the least, and involves many other factors,including just plain chance. KERRY EMANUEL: Hurricanes are like any phenomenon in the atmosphere,creatures of chance. If you're interested in any given storm, it is the roll ofthe die. And the whole question is whether that die is weighted. CHAD COHEN: The problem with hurricanes is that we can neversay for sure what exactly happens. There's always an element of chance. So wetake the temperature of the water, measure the amount of moisture in theatmosphere, we look at what the winds are doing, and depending on how all thosefactors come together, we get a probability that a hurricane will become eithera Category 1, a 2, a Category 3, 4 or 5. KERRY EMANUEL: I think there's little doubt that we are loading the die.We're causing global warming. The tropical temperatures are going up. CHAD COHEN: But whether global warming is having an impact onhurricanes, well, not every scientist agrees, even those on the front lines ofstorm forecasting. CHRIS LANDSEA (National Hurricane Center): A hurricane waspredicted to come ashore. CHAD COHEN: Last October, as Hurricane Wilma was poised to hitFlorida, Chris Landsea, at the National Hurricane Center in Miami, helped trackthe powerful storm. CHRIS LANDSEA: There's distinct cycles of hurricane activity in theAtlantic, that it tends to go 25 or 40 years very busy, and 25 to 40 yearsfairly quiet. KERRY EMANUEL: If all we had to go on was the hurricane data, I don'tthink we would be terribly alarmed. We'd just say, well, there...you know, it'sbeen changing the last 25, 30 years, so what? It's the correlation with seasurface temperature and the fact that that trend is unprecedented for a longtime that has us worried. CHRIS LANDSEA: We're not seeing unprecedented. We're seeing the sametype of hurricane activity that we saw in the middle part of the 20th century.And it actually may have been busier back then, than it is now. KERRY EMANUEL: A lot of things in science, sometimes there isn't asmoking gun. There isn't one piece of evidence that everybody looks at andsays, "Yeah, you know, that proves that global warming is affectinghurricanes." What you have are multiple pieces of evidence which all point inthe same direction. CHAD COHEN: This high stakes debate will only be resolved withmore data, and that won't be a problem. Hurricane season is never too faraway. Broadcast Credits Stronger Hurricanes Executive Producer Samuel Fine Executive Editor Robert Krulwich Senior Series Producer Vincent Liota Senior Producer Robe Imbriano Producers Julia Cort Carla Denly Robe Imbriano Dean Irwin Vincent Liota Mary Robertson Win Rosenfeld Editors Ben Ehrlich Nathan Hendrie Robe Imbriano Vincent Liota Win Rosenfeld Supervising Producer Andrea Cross Development Producer Kyla Dunn Program Editor Steve Trevisan Associate Producers Anthony Manupelli Mary Robertson Win Rosenfeld Ayo Babatunde Shimona Shahi Unit Manager Candace White Production Secretary Ayo Babatunde Compositing Yunsik Noh Production Assistant Robbie Gemmel Music Rob Morsberger NOVA scienceNOW Series Animation Edgeworx Camera Chris Borghesani George Delgado Brian Dowley Tom Fahey Vikram Gandhi Robert Hanna Michael Hunkley Sound Recordists Paul Austin Vikram Gandhi Mike Karas Dennis McCarthy Gilles Morin Alex Sullivan Audio Mix John Jenkins Animation Mitch Butler Edgeworx Picket Design Pie Design Special Thanks Clifford Cunningham Foxwoods Resort Casino The Graduate Center at CUNY Alex Meissner NaturallyTasty Health Food The New York Number Theory Seminar The officers and crew of the NOAA ships Delaware II and Albatross IV János Pintz Salon Mario Russo Cem Yildirim Adam Zoghlin Archival Material ABC News Video Source Art. Lebedev Studio Mike Brown, Caltech Michael Brumlik Jewel Webb Chambers CNN CORBIS Motion Michael DiGiorgio, Worldwide Nature Artists Group Denis Finnin, American Museum of Natural History Richard Gibbe Dennis Kunkel Microscopy, Inc. Robert Hurt (IPAC) Jupiterimages Corporation The Macaulay Library at the Cornell Lab of Ornithology MODIS Rapid Response Project at NASA/GSF Museum of Comparative Zoology, Harvard University NASA/JPL NASA/JPL-Caltech Jay Pitocchelli Prairie Pictures / StormStock, Martin Lisius 24 Images N. John Schmitt UltimateChase Stock Video Mitch Waite WWL-TV NOVA Series Graphics yU + co. NOVA Theme Music WalterWerzowa John Luker Musikvergnuegen, Inc. Additional NOVA Theme Music Ray Loring Post Production Online Editor SpencerGentry Closed Captioning The Caption Center NOVA Administrator Dara Bourne Publicity Eileen Campion Olivia Wong Senior Researcher Barbara Moran Production Coordinator LindaCallahan Unit Managers LolaNorman-Salako Carla Raimer Paralegal Richard Parr Legal Counsel SusanRosen Shishko Post Production Assistant Alex Kreuter Associate Producer, Post Production Patrick Carey Post Production Supervisor ReginaO'Toole Post Production Editor RebeccaNieto Post Production Manager Nathan Gunner Supervising Producer StephenSweigart Producer, Special Projects Susanne Simpson Coordinating Producer LaurieCahalane Senior Science Editor EvanHadingham Senior Series Producer MelanieWallace Managing Director Alan Ritsko Senior Executive Producer PaulaS. Apsell NOVA scienceNOW is a trademark of the WGBH Educational Foundation This material is based upon work supported by the National Science Foundationunder Grant No. 0229297. Any opinions, findings, and conclusions orrecommendations expressed in this material are those of the author(s) and donot necessarily reflect the views of the National Science Foundation. © 2006 WGBHEducational Foundation All rights reserved Image credit: (Hurricane Katrina) Courtesy NASA Participants Chad Cohen Correspondent Kerry Emmanuel Professor of Tropical Meteorology and Climate, Massachusetts Institute of Technology Christopher Landsea Science and Operations officer, National Hurricane Center Peter Webster Professor of Earth and Atmospheric Sciences, Georgia Institute of Technology Related Links Hotter Oceans, Fiercer Storms In this audio slide show, examine the link between rising sea surface temperature and more intense storms. Hurricane Katrina: Expert Q&A Research meteorologist Marshall Shepherd answers questions about hurricanes and the ongoing threat to New Orleans. Calling Katrina Jonah Lehrer discusses new research into hurricanes that may help explain Katrina's devastating impact. Hurricane Power Your average hurricane releases enough energy to power the world 200 times over. Go figure. TV Schedule Teachers Shop NOVA Search NOVA Beta Planet Earth Resources Text (45) Earthquakes: Expert Q&A Seismologist Frank Vernon answers questions about earthquakes past, present, and future. Filming in a Disaster Area Director Daniel Hissen felt equal parts inspiration and anxiety while shooting amidst the devastation. Risking It All for Science What drives scientists to delve into flooded caves where they face rock falls, nitrogen narcosis, even drowning? Sang-Mook Lee: Expert Q&A Sang-Mook Lee, a physically disabled South Korean scientist, answers questions about his life and work. Midwest Earthquakes: Expert Q&A Geophysicist Beatrice Magnani answers questions about the New Madrid Seismic Zone and its deadly potential. Video (23) Deadliest Volcanoes From Japan’s Mt. Fuji to Yellowstone’s buried supervolcano, how can we best prepare for the most lethal eruptions? Ice Age Death Trap Racing against developers, experts uncover a site in the Rockies packed with fossil mammoths and other extinct beasts. Surviving the Tsunami Gripping personal stories from Japan offer lessons on how to act in the face of a life-threatening disaster. Japan's Killer Quake An eyewitness account and investigation of the epic earthquake, tsunami, and nuclear crisis Detecting Earthquakes Can we predict earthquakes? NOVA scienceNOW visits Haiti and California in search of answers. Multimedia (36) Find the Tectonic Fault In this seismic image, see if you can locate an unsettling new fault just discovered beneath the Mississippi River. Hear From Sang-Mook Lee The Korean oceanographer and spokesman for the disabled talks about the blessings of a debilitating accident. Exploring the Arctic Seafloor See some of the first imagery ever shot on the Arctic Ocean seabed—and what it's telling us about living at extremes. Hear From the Real Iceman Lonnie Thompson discusses why we should care that glaciers are melting, why sea-level rise is only part of it, and more. Trapped in Salt Biophysicist Jack Griffith takes you on a narrated photo tour of quarter-billion-year-old water bubbles. Audio (2) Extinction Happens MIT geologist Sam Bowring muses on mass extinctions and why we can’t take Earth’s hospitable climate for granted. Tracking Twisters With Radar Can new weather radar networks spot tornadoes earlier and thereby save lives? NOVA Education Close Home About this Beta About NOVA Credits Shop NOVA FAQs Newsletter PBS Privacy Policy RSS Feed Feedback Support NOVA Education Corporate Sponsorship This website was produced for PBS Online by WGBH. Website © 1996–2011 WGBH Educational Foundation Funding for NOVA scienceNOW is provided by the National Science Foundation, the Howard Hughes Medical Institute, the Alfred P. Sloan Foundation, and PBS viewers. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, Lockheed Martin Corporation, and PBS viewers.