Global Climate Change, Weather, and Disasters

Transcription

1 Global Climate Change, Weather, and Disasters The Hype and the Available Data! K.E. Kelly

2 Is Climate Change Causing Extreme Weather? New Republic Zogby Analytics poll shortly after hurricane Sandy A strong majority (57 percent) says climate change is adding to the severity of recent extreme weather such as Superstorm Sandy and the summer droughts.

3 How Can Climate Change Any Ideas? Affect Severe Weather Rates of evapotranspiration (from soil, plants and water) increase, which can affect rainfall and droughts. A warmer atmosphere holds more water, which can affect the intensity of rainfall events. Changes in ocean surface temperature can alter ocean circulation, atmospheric circulation, and precipitation.

4 Changes in Distribution Can Change the Extremes Mean temperature increases (distribution same). Increased temperature variability (mean same). Asymetrical distribution. The effect of changes in temperature distribution on extremes (IPCC 2011). Dotted vertical line shows mean. Solid distribution: without climate change; dotted distribution: with climate change.

5 IPCC Highlights: Uncertainty Challenges: - How to account for natural variability, especially for rare events. - Lack of data, confounding factors - Prediction (especially about the future) and understanding the underlying process Higher quality data: - Temperatures - Sea level

6 What We Know: Ocean Heat Content Lines independently calculated using different methods by three agencies: the National Oceanic and Atmospheric Administration (NOAA), Australia s Commonwealth Scientific and Industrial Research Organisation (CSIRO), and Japan Meteorological Agency s Meteorological Research Institute (MRI/JMA). from

7 What We Know: Ocean Temperatures From 1901 through 2013, temperatures rose at an average rate of 0.13 F per decade. Earlier data have less certainty because of lower sampling frequency and less precise sampling methods. from

8 IPCC Highlights: Temperature Very likely decrease in the number of cold nights and increase of the number of warm days (North America, Europe, Australia). Likely increase in temperature extremes in Asia. Medium to low confidence for a change in temperature extremes in Africa. Medium confidence that the length and number of warm spells or heat waves has increased.

9 IPCC Highlights: Temperature Prediction Virtually certain of an increase in the frequency and magnitude of warm daily temperature extremes and a decrease in cold extremes. Very likely an increase in the length, frequency and intensity of heat waves.

10 What We Know: Sea Level Change Since 1880, sea level rose 0.06 inch/yr Since 1993, sea levels rose inches/yr Average absolute sea level change, the height of the ocean surface, measured from the center of the earth, regardless of whether nearby land is rising or falling From

11 IPCC Highlights: Water It is likely that there has been an increase in extreme coastal high water related to increases in mean sea level. Medium confidence that some regions (Europe & West Africa) have experienced more intense and longer droughts. Other regions have experienced less drought (North America and NW Australia). Limited evidence to assess climate-driven changes in flood frequency (data challenges and land-use changes). Although there are regional differences, there are statistically significant increases in the number of heavy precipitation events.

12 IPCC Highlights: Water Prediction Highly likely sea levels will continue to increase. Likely that the frequency of heavy precipitation events will increase Limited evidence to assess climate-driven changes in flood frequency and severity (data challenges and land-use changes).

13 Highlights: Cyclones and Tornados Low confidence in any long-term increases in cyclone activity Likely increases in average maximum wind speed Heavy rainfall associated with hurricanes likely to increase Projected sea level rise is expected to compound storm surge impacts. Difficult to predict impacts with geospatial resolution Low confidence in observed trends in small spatial-scale phenomena such as tornadoes and hail (data inhomogeneities an inadequacies in monitoring systems)

14 IPCC Highlights: Economic Impacts Economic losses (damaged assets) from weather- and climate-related disasters have increased (great annual variations) Annual worldwide losses range from a few billion t0 $200 billion (US 2010 dollars, Hurricane Katrina biggest year) Difficult to monetize a variety of impacts Economic losses are greatest in developed countries but losses as a fraction of GDP are greatest in developing countries.

15 US Billion Dollar Weather Disasters a statistically significant increasing trend of about 5 % per year in the frequency of billion-dollar disasters! A.B. Smith, R.W. Katz (2013) US billion-dollar weather and climate disasters: data sources, trends, accuracy and biases Natural Hazards Volume 67, Issue 2,

16 Climate, Weather and Disaster Risk

17 Exposure & Vulnerability Effects of a tornado differ dramatically depending on where it touches down. Extreme heat affects different populations (vulnerable populations old, low income) differently. Populations in coastal, megadeltas and the mountains are more vulnerable. Effects can compound, i.e., drought and extreme heat = wildfires.

18 Adaptation: Managing Risks

19 Adaptation: Managing Risks Low-regret strategies: Early-warning systems (i.e., tornados and hurricanes) Disaster preparedness and communication Smart land-use strategies (i.e., preserving coastal wetlands, siting critical infrastructure) Development and enforcement of building codes Adequate sanitation, drainage and irrigation systems

20 Potential Resources indicators/weather-climate/index.html extreme-events publication/ WEO_Special_Report_2013_Redrawing_the_Energy_ Climate_Map.pdf