LATEST UPDATE ON CLIMATE CHANGE Steven W. Running Numerical Terradynamic Simulation Group University of Montana NOVEMBER , 2005

Intergovernmental Panel on Climate Change, 2000 Global Warming Intergovernmental Panel on Climate Change, 2000 “The Earth’s climate system has demonstrably changed on both global and regional scales since the pre-industrial era, with some of these changes attributable to human activities.” American Geophysical Union, 2003 “Human activities are increasingly altering the Earth’s climate”

Dai et al. J. Hydromet (2004)

CLIMATE TRENDS for the last century

Temperature Trends: 1901 to 1998 Red circles reflect warming; Blue circles reflect cooling All Stations/Trends displayed regardless of statistical significance. Source: National Climatic Data Center/NESDIS/NOAA

Precipitation Trends: 1901 to 1998 Blue circles reflect increasing precipitation; Red circles reflect decreasing precipitation All Stations/Trends displayed regardless of statistical significance. Source: National Climatic Data Center/NESDIS/NOAA

“Simulations of the response to natural forcings alone … do not explain the warming in the second half of the century” SPM Stott et al, Science 2000

“..model estimates that take into account both greenhouse gases and sulphate aerosols are consistent with observations over this period” SPM Stott et al, Science 2000

Aircraft Contrails, Jan 29 2004 MODIS Contrail clouds warmed Earth 0.2degC/decade. Minnis, 2004

OBSERVED EARTH SYSTEMS RESPONSES

Global ocean circulation Cooling Warm surface current Intermediate waters Warm and less saline Antarctic circumpolar current A simplified view of the global thermohaline conveyor belt, showing cooling and downwelling in the North Atlantic, warming and freshening in the southern hemisphere, and return flow as a warm surface current.

[1979 – 2002]

Comparison of the heat balance of the climate system Levitus et al (2001). Science Vol. 292, pp. 268.

Increase in Hurricane Intensity PDI = Potential Destructiveness Index Emanuel, Nature 4 August 2005

Increase in Category 4-5 Hurricanes 1970 - 2004 Webster et al, Science, Sept 16 2005

Webster et al Science Sept 16, 2005

Arctic sea ice gets thinner

From SMMR data

Montana = 0.38million km2 National Snow and Ice Data Center

Montana = 376,000km2

ALASKAN GLACIER MASS BALANCES 1950 - 2001 Arendt et al 2002. Science.

Antarctic Glaciers 1945-2004 Cook et al 2005. Science

The South Cascade glacier, Washington 1928 Other evidence for warming comes from glaciers. These pictures show the South Cascade glacier in 1928 and 2000. The glacier has retreated and thinned substantially, leaving a glacial lake in its place. Glacial retreats have occurred around the world. Courtesy of the USGS glacier group 2000

Flood

Percent of the continental USA with a much above normal proportion of total annual precipitation from 1-day extreme events (more than 2 inches or 50.8mm) BW 7 Karl et al. 1996

OBSERVED BIOSPHERIC RESPONSES

Spring bud-burst dates for Aspen in Edmonton, Beaubien and Freeland I Spring bud-burst dates for Aspen in Edmonton, Beaubien and Freeland I.J.Biomet 44:53-59, 2000

The increase in growing season length over the last 50 years averaged for eight stations in Alaska having the longest and most consistent temperature records.

Change in Terrestrial NPP from 1982 to 1999. Nemani et al., Science June 6th 2003

BLEACHING OF CORAL REEFS BY OCEAN TEMPS > 85deg

Locations of Coral Reef Bleaching

CHANGE IN OCEAN NPP [1979 – 2002]

Human Mortality Attributable to Climate Change thru 2000 (heat stress, malnutrition, malaria, flooding, etc.) Patz, et al Nature 438: 310-317, 2005

MISSOULA CLIMATE TRENDS SINCE 1950

Decrease Increase Manual snow course measurements have been taken since the 1920s in a few places. Around April 1 the most common time of year. Trends at most locations are negative. Largest decreases are generally at lowest elevation, especially in the Oregon Cascades. the declines in snow occur in spite of increases in precipitation. These results from Mote, P.W. 2003. “Trends in Snow Water Equivalent in the Pacific Northwest and Their Climatic Causes”, Geophysical Research Letters (in press). Mote 2003(b)

Trends in timing of spring snowmelt (1948-2000) Yet another piece of evidence of warming came from this paper (Cayan et al., Bulletin of the American Meteorological Society, 2001). The timing of peak spring snowmelt (and of biological events like blooming and leafing-out dates of plants) has tended toward earlier dates over the last 50 years. These dates are highly correlated with spring temperature. +20d later –20d earlier Courtesy of Mike Dettinger, Iris Stewart, Dan Cayan

INCREASING WILDFIRE IN CANADA Gillette et al 2004

Projected PNW Climate Trends Projected changes in average annual PNW temperature and precipitation for the decades of the 2020s and 2040s. 2020s Temperature Precipitation Low + 0.9°F + 2 % Mean + 2.4°F + 7% High + 3.4°F + 14 % 2040s Temperature Precipitation Low + 2.7°F - 3 % Mean +4.0°F + 7% High + 4.9°F + 14 % Looking at what 8 models say for the Pacific Northwest, with a simple CO2 scenario (increasing 1%/year) the average of the changes is about 0.45C/decade with slight increases in precipitation. Precipitation is more difficult to simulate well, so we have less confidence in projections of future precipitation than in projections of future temperature. Based on an increase in equivalent CO2 of 1% per year. Benchmarked to the decade of the 1990s.

THE S.W. RUNNING CRYSTAL BALL, MONTANA FOR THE NEXT 50 YEARS EXPECTED MONTANA CLIMATE TRENDS Shorter, milder winters Earlier snowmelt Longer growing seasons Decreasing summer streamflows More drought and fire danger Precipitation???

EXPECTED MONTANA ECOSYSTEM TRENDS - Earlier crop planting dates More forest/range/crop productivity Decreased deer/elk winterkill Hibernating animals? Increased forest insect/disease trends More aquatic ecosystem degradation, low dissolved O2, high water temps More aquatic recreation limits

China Smog, Nov 4, 2005

Variations of the Earth’s surface temperature; 1000 to 2100