Hurricane-Curry Guadeloupe
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Global Climate Change and Hurricanes: the Science, the Controversy & the Risk Judith A. Curry Deadliest Hurricanes to Hit Central America and the Caribbean Storm Deaths Locations Affected Great Hurricane of 1780 >22,000 Barbados, Martinique Hurricane Mitch (1998) 11,000 – 18,000 Honduras, Nicaragua Hurricane Fifi (1974) 8,000 – 10,000 Belize, Guatemala, Honduras Hurricane Flora (1963) 7,186 – 8,000 Tobago, Hispaniola, Cuba 1930 Dominican Republic Hurricane 2,000 – 8,000 Hispaniola, Cuba Pointe-a-Pitre Bay Hurricane (1776) >6,000 Martinique, Guadeloupe San Ciriaco Hurricane (1899) 3,433 Puerto Rico 1932 Cuba Hurricane 3,033 Cuba, Bahamas 1934 Yucatan Hurricane 1,000 – 3,000 Belize, Guatemala, El Salvador, Honduras 1931 Belize Hurricane 2,500 Belize, Guatemala Hurricane Stan (2005) 1,620 Guatemala, El Salvador, Nicaragua, Honduras, Costa Rica Atlantic Landfalling Storms Striking CentralHurricane Strength AmericaDistribution for Landfalling and Storms inthe Central AmericaCaribbean and the Carribean 35 30 25 20 15 Number of Systems 10 5 0 1951-1955 1956-1960 1961-1965 1966-1970 1971-1975 1976-1980 1981-1985 1986-1990 1991-1995 1996-2000 2001-2005 Year Tropical Storms/Depressions Cat 1&2 Cat 3, 4, 5 Are more hurricanes a harbinger of the Caribbean’s future? To assess the Caribbean’s risk from landfalling hurricanes in the coming decades, we must understand: . Impact of global warming on hurricane activity . Natural variability in the Atlantic Ocean . Nature of local risks INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE WMO 4th Assessment Report UNEP Summary for Policy Makers “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.” “Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely [>90%] due to the observed increase in anthropogenic greenhouse gas concentrations.” UNEP Warmest 12 years: 1998,2005,2003,2002,2004,2006, 2001,1997,1995,1999,1990,2000 Global surface temperature has increased 0.74oC since 1906 Meehl et al, 2004 Increased global temperatures since 1970 is attributed to greenhouse warming IPCC AR4: Hurricanes WMO Detection of Change UNEP . There is observational evidence for an increase of intense tropical cyclone activity in the North Atlantic since about 1970, correlated with increases of tropical sea surface temperatures . There are suggestions of increased intense tropical cyclone activity in other regions where concerns over data quality are greater . Multi-decadal variability and the quality of the tropical cyclone records prior to 1970 complicate the detection of long-term trends in tropical cyclone activity UNEP North Atlantic Tropical Cyclones and SST 11 year running mean surface aircraft satellite recon Increased tropical cyclone activity since 1970, correlated with increasing sea surface temperatures Global View of Tropical Cyclones W. Pacific Ocean N. Atlantic Ocean 40% 11% N. Indian Ocean E. Pacific Ocean 6% 17% S. Indian Ocean SW Pacific Ocean 19% 8% Each year there are about 85-90 tropical cyclones globally Global tropical cyclone intensity Webster, Holland, Curry, Chang (2005) Science # of cat 4+5 hurricanes has doubled globally since 1970 Data quality questioned in the Indian Ocean, Pacific Ocean Wall Street Journal February 2, 2006 Cold Front Debate Shatters Civility of Weather Science Hurricanes Worsened by Global Warming? Spats are so tempestuous, sides are barely talking Charge of “brain fossilization” Tropical cyclone genesis/intensification factors Sea water temperature > 26.5oC. Major hurricanes >28.5oC Small vertical shear (minimal variation of wind with height) Moist mid-troposphere & convective instability Pre-existing weather disturbance Not too close to the equator These factors change both with natural climate variability (e.g., El Nino) and global warming Global trends in the tropics since 1970 Sea surface temperature Wind shear 0.5oC (1oF) increase no trend Hoyos et al. 2006 IPCC AR4: Hurricanes WMO Projections of Future Change UNEP . It is likely [>66%] that future tropical cyclones will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical SSTs . The apparent increase in the proportion of very intense storms since 1970 in some regions is much larger than simulated by current models for that period UNEP TC intensity - SST link Hurricane intensity change scaled for a 0.5oC SST increase: Webster et al. obs: +6.0% Climate models: Knutsen/Tuleya (2004): +2.0% Oouchi et al. (2006): +2.1% Potential intensity theory: Emanuel +2.7% Holland +5.3% 3-legged stool analogy: Observations, theory, and climate models agree that hurricane intensity should increase; they disagree on the magnitude of the increase. The stool stands. Intensity Distribution of North Atlantic Tropical Cyclones 50% 45% 40% 35% TS 30% Cat1 Cat2 25% Cat3 20% Cat4 15% Cat5 10% 5% 0% 1970-1982 1983-1994 1995-2006 Since 1995, there has been a shift in the intensity distribution towards more major hurricanes What does the future hold for hurricane activity in the North Atlantic? Combined impacts of greenhouse warming and natural variability ClimateThe uncertain Model climate Projections future WMO UNEP Jkljl Jlkjlj Lhjljk Scenario simulations indicate 1.8-4.0oC temperature increase by 2100 Climate model projections of future hurricane activity For a 2.5oC temperature increase: • up to 30% increase in number of N. Atlantic tropical cyclones (no increase or slight decrease in global numbers) • 10% increase in tropical cyclone intensity • 30% increase in the number of major hurricanes Relationship between # of Atlantic storms and sea-surface temperature Obs: 1oF increase in SST --> +5 storms/year Model: 1oF increase in SST --> +1 storm /year North Atlantic Ocean 11 year centered running mean 14 Atlantic Multidecadal Oscillation (AMO) 12 10 8 6 Number of Storms 4 2 0 1850 1870 1890 1910 1930 1950 1970 1990 2010 Named Storms Hurricanes Cat. 4&5 Since 1995, there has been 40-50% greater activity than the previous peak period ca. 1950 Projections for the average number of NATL tropical cyclones for 2025 (0.5oC warming) # of Tropical Cyclones: • Avg for last 50 yrs: 10 • Avg last decade: 14 • Avg ca. 2025: 15-20 category 4+5 3-4 The combination of greenhouse warming and natural variability will produce unprecedented tropical cyclone activity in the coming decades What does the increase in North Atlantic hurricane activity mean for the Caribbean? Landfalling tropical cyclones striking the Caribbean and Central America 18 16 14 12 10 8 6 4 2 0 1900 1920 1940 1960 1980 2000 Hurricane Landfall Location 25% 1900-2006 1900-1969 1970-2006 20% 15% 10% 5% 0% T&T Cuba Haiti Rico Belize / Mexico Republic HondurasNicaragua Bahamas Puerto Lesser Antilles Mexico(Yucatan) Venezuela Jamaica/Caymans Dominican SST Changes: Gulf of Mexico and Caribbean Warmest decade Summary: Projection for next two decades . The number of North Atlantic tropical cyclones most likely will increase in coming decades and intensity is expected to continue to increase . The number of Caribbean landfalls will most likely continue to increase UNEP.