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Impacts of Climate Change Impacts on Natural Systems Impacts on Society: water , agriculture, food, and human health. CLIM 101: Global Warming: Weather , Climate and Society. Weather Climate. Ecosystems. Humans. Global Sea Level. From AVISO.oceanobs.com.
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Impacts of Climate ChangeImpacts on Natural SystemsImpacts on Society: water, agriculture, food, and human health CLIM 101: Global Warming: Weather, Climate and Society
Weather Climate Ecosystems Humans
Global Sea Level From AVISO.oceanobs.com
Sea Level Rise over the Last 150 Years Sea level rise in mm from 1860 onward based on a merging of three different datasets. 0.17 m (7.5”) since 1900 base period Reconstructed fields since 1870 Coastal tide gauges Satellite altimetry
Changes in Cryosphere • Cryosphere • Consists of: snow, river and lake ice, sea ice, ice shelves and ice sheets, glaciers and ice caps, frozen ground • 2nd largest component of the climate system (75% of fresh water) • Linked to energy budget (reflection of solar radiation) • Natural sensor of climate variability (“canary in the mine”) • Important climate change variable • Snow cover • Polar Sea ice – Arctic and Antarctic • Continental Ice Sheet – Greenland and Antarctic • Mountain Glaciers – Tropics and mid-latitude • Permafrost (Frozen Ground)
Arctic Sea Ice is Disappearing 2007: 38% below average 2008: 34% below average
7Mar2011 15Sep2011
Greenland Ice Sheet Melt Nearly 2 Trillion Tons of Ice Melt since 2003 (Enough to fill 20 Chesapeake Bays) Melting Greenland ice sheet would raise global sea level by 7 m.
Based on GRACE data
Permafrost (Frozen Ground) Northern Hemisphere Frozen Ground Seasonally Frozen Ground Intermittently Frozen Ground
Changes in Cryosphere • Snow decrease • Lake and river ice: Later formation and earlier melt • Sea ice extent decrease • Loss of glaciers and ice sheets • Sea level rise • Permafrost loss
IPCC AR4 WG-II Report • Chapter 3 - Fresh Water • Chapter 5 - Food • Chapter 8 - Impacts on human health http://www.ipcc.ch/ipccreports/ar4-wg2.htm
Center of Ocean-Land-Atmosphere studies South Asian Adaptation
Monsoon Drought in 2009 South Asian Adaptation
Monsoon Drought in 2009 Extreme Pakistan Floods in 2010 South Asian Adaptation
Impacts on Human Health • Climate change contributes to the global burden of disease and premature deaths • Climate change has: • altered thedistribution of some infectious disease vectors • altered the seasonal distribution of some allergenic pollen species • increasedheatwave-related deaths • Projected trends will: • increase malnutrition, inhibit child growth and development • increase deaths, incidence of disease and injury from heat waves, floods, storms, fires and droughts • continue to change the range of some infectious disease vectors • have mixed effects on malaria; in some places the geographical range will contract, elsewhere the geographical range will expand and the transmission season may be changed • increase the burden of diarrheal diseases • increase cardio-respiratory morbidity and mortality associated with ground-level O3 • increase the number of people at risk of dengue • decrease deaths from cold • Adaptive capacity needs to be improved everywhere • Adverse health impacts will be greatest in low-income countries. Those at greater risk include, in all countries, the urban poor, the elderly and children, traditional societies, subsistence farmers, and coastal populations
Climate and Malaria • Temperature dependence of malaria vector well known to researchers in the 1920s (e.g., A. Macdonald, Journal of the Royal Army Medical Corps) • Maximum altitude and latitudinal range strongly determined by mean temperature • Interactions between pathogen, vector, host, and climate are complex and not fully understood • Weaker links between disease incidence and climate within endemic regions • Vectors are subject to significant control measures in developed world, confounding link to climate.
Cholera • Cholera • Pathogen (vibrio cholerae) inhabits aquatic environments • Fecal-oral transmission • Ingestion of contaminated water • Numerous pandemics throughout history • Symptoms: diarrhea, vomiting, nausea • Death through dehydration, loss of electrolytes • Treatable • Bangladesh • Endemic center of cholera • Low-lying • Densely populated • Delta of two major rivers
What is Lyme disease? • Multisystem disease in humans (and animals) caused by a spirochaetebacterium Borreliaburgdorferi • Non-fatal but chronic and debilitating if not treated early • Difficult to diagnose by doctors (clinical presentation and serology) • ~ 20,000 cases a year in USA despite high level of awareness by the public & medical practitioners • Infects wildlife (rodents, birds, mustelids NOT deer); transmitted from one animal to another by ticks • Ticks are not very choosy about who they bite and bite people by accident • The geographic range of Lyme disease is tied to that of its tick vectors
Impact of Climate Change on Lyme Disease in Canada • A northward expansion of the range of Ixodesscapularis, associated with climate change, is likely because: • Tick survival increases dramatically • Ticks are being carried into Canada each year on migratory birds • The habitat in many areas is suitable for tick survival • Chaotic weather (heavy rainfall and droughts) may inhibit spread • Spread into central Provinces may be limited by low rainfall
Fresh Water Resources and their Management • The impacts of climate change on freshwater systems and their management are mainly due to the observed and projected increases in temperature, sea level and precipitationvariability. • Semi-arid and arid areas are particularly exposed to the impacts of climate change on freshwater. • Higher water temperatures, increased precipitation intensity, and longer periods of low flows exacerbate many forms of water pollution, with impacts on ecosystems, human health, water system reliability and operating costs. • Climate change affects the function and operation of existing water infrastructure as well as water management practices. • Adaptation procedures and risk management practices for the water sector are being developed in some countries and regions (e.g., Caribbean, Canada, Australia, Netherlands, UK, USA, Germany) that have recognized projected hydrological changes with related uncertainties. • The negative impacts of climate change on freshwater systems outweigh its benefits.
Impact of Climate Change on World Food Prices Cereal prices versus global mean temperature change
Summary • Projected changes in the frequency and severity of extreme climate events will have more serious consequences for food and forestry production, and food insecurity, than will changes in projected means of temperature and precipitation. • Climate change increases the number of people at risk of hunger (high confidence). The impact of chosen socioeconomic pathways (SRES scenario) on the numbers of people at risk of hunger is significantly greater than the impact of climate change. Climate change will further shift the focus of food insecurity to sub-Saharan Africa. • While moderate warming benefits crop and pasture yields in mid- to high-latitude regions, even slight warming decreases yields in seasonally dry and low-latitude regions. • Experimental research on crop response to elevated CO2 confirms Third Assessment Report (TAR) findings). New Free-Air Carbon Dioxide Enrichment (FACE) results suggest lower responses for forests. Cropmodels include CO2 estimates close to the upper range of new research (high confidence), while forest models may overestimate CO2 effects. • Globally, commercial timber productivity rises modestly with climate change in the short and medium term, with large regional variability around the global trend. • Local extinctions of particular fish species are expected at edges of ranges. • Food and forestry trade is projected to increase in response to climate change, with increased dependence of most developing countries on food imports. • Simulations suggest rising relative benefits of adaptation with low to moderate warming, although adaptation may stress water and environmental resources as warming increases.
What is in store for the future and what has already been committed CO2 Eq Global warming will increase if GHGs concentration increase. Even if GHGs were kept constant at current levels, there is a “commitment” of 0.6°C of additional warming by 2100. 3.4oC = 6.1oF 850 2.8oC = 5.0oF 600 1.8oC = 3.2oF 400 0.6oC = 1.0oF
Global Mean Sea Level Relative to the 1980 to 1999 mean
IPCC AR4 Working Group II Report "Impacts, Adaptation and Vulnerability" • • Chapter 4 - Ecosystems, their Properties, Goods and Services • Chapter 6 - Costal system and low-lying areas • Chapter 7 - Industry, settlement and society • • Chapter 3 - Fresh Water Resources and their Management • • Chapter 5 - Food, Fibre, and Forest Products • Chapter 8 - Impacts on human health http://www.ipcc.ch/ipccreports/ar4-wg2.htm
Vulnerability • 30 to 200 million people at risk of hunger with temperature rises of 2 to 3°C • 0.7 to 4.4 billion people will experience growing water shortages with a rise of 2°C Yields across Africa and Western Asia may fall by 15% to 35%
Ecological impacts of the European heatwave 2003 Relationships between the percentage of species loss and anomalies of moisture availability and growing-degree days Future projections for Europe suggest significant reductions in species richness even under mean climate change conditions, and an increased frequency of such extremes is likely to exacerbate overall biodiversity losses. Thuiller W. et.al. PNAS 2005;102:8245-8250
Wanted: New Home for My Country Mohamed Nasheed Former President of the Maldives
Coastal areas are at increasing risk from sea-level rise and storm surge. Florida with 3 feet of Sea-Level Rise
Impacts on Industry, Settlement and Society • Climate-change vulnerabilities of industry, settlement andsociety are mainly related to extreme weather eventsratherthan to gradual climate change • Aside from major extreme events and thresholds, climatechange is seldom the main factor in considering stresses onthe sustainability of industry, settlements and society • Vulnerabilities to climate change depend considerably onspecific geographic, sectoral and social contexts • Vulnerabilities of industry, infrastructures, settlements andsociety to climate change are generally greater in certainhigh-risk locations, particularly coastal and riverine areas,and areas whose economies are closely linked with climate-sensitive resources, such as agricultural and forest productindustries, water demands and tourism; these vulnerabilitiestend to be localized but are often large and growing • Poor communities can be especially vulnerable, in particularthose concentrated in relatively high-risk areas • Industry, settlements and society are often capable ofconsiderable adaptation, depending heavily on thecompetence and capacity of individuals, communities,enterprises and local governments, together with access tofinancial and other resources • Although most adaptations reflect local circumstances,adaptation strategies for industry and settlement and, to alesser degree, for society, can be supported by linkages withnational and global systems that increase potentials andresources for action
Hurricane Katrina • Landfall on Gulf Coast of US on 29 August 2005 (category 3; several days at category 5 in Gulf) • Widespread flooding, levee failures in New Orleans (80% of city), Louisiana and Mississippi • Collapse of I-10 bridge cut off New Orleans exit to east • Loss of life: 1,464 • Damage to many downtown buildings, Superdome, Convention Center • Civil unrest in New Orleans; refugees turned away from Gretna, LA at gunpoint
Record Heat Wave – Western Russia 2010 • Highest temperatures in 130 years • Spontaneous fires – peat bogs, crops, forests • 70+ deaths from fire, 2000+ deaths from drowning
PDSI in the 20th Century • Eastern North& South America, northern Eurasia are getting wetter • Africa is getting drier, especially in Sahel • Very dry areas have more than doubled since the 1970s.
Do the rains follow the plough.... ... or does agriculture promote desertification? U.S. Dust Bowl - 1930s
Global Warming and Drought • Droughts have multiple causes • land abuse • increasing demand on limited water resources • anomalous sea surface temperature patterns • We can’t attribute specific droughts to global warming • but we can say with some confidence • that global warming is likely to increase the incidence of drought, especially in semi-arid regions. • Drought and desertification, in turn, lead to higher daytime temperatures
Origins of Floods • Flash Floods are typically caused by short, intense rainfall events over areas as small as a city to larger than a state. • Riverine Flooding: Widespread excessive rain events produce flooding along waterways throughout the United States. • Hurricanes: Warm, moist tropical air that serves to drive the winds in a hurricane can also lead to widespread hazardous flooding. • Ice Jam Floods • Snow Melt Floods: Warm, moist conditions and heavy rain can combine with snow melt to cause dramatic winter and spring flooding.
Are floods increasing? • Trends in the frequency of flood events are difficult to quantify because • River configurations and land use are continually changing • Hourly rainfall data are available only over limited regions of the globe • the data are expensive and there are restrictions on their use • Floods are rare events, especially when considered season-by-season • Like keeping track of “grand slam” home runs • it’s difficult to establish statistical significance when dealing with rare events. But we believe floods should become more frequent because warmer air holds more water vapor.