MET MET 112 Global Climate Change: Lecture 13 Climate Change Impacts: Present and Future II Dr. Craig Clements

MET Climate Change Impacts  What signals would we expect from a warmer world? –Higher average temperature –Higher maximum temperatures –Higher minimum temperatures –More precipitation –Higher sea level  What ‘evidence’ do we have for changes in the 20th century?

MET  FINGERPRINTS: Direct manifestations of a widespread and long-term trend toward warmer global temperatures – Heat waves and periods of unusually warm weather – Ocean warming, sea-level rise and coastal flooding – Glaciers melting – Arctic and Antarctic warming – Increases in sea level Fingerprints and harbingers of climate change

MET  HARBINGERS: Events that foreshadow the types of impacts likely to become more frequent and widespread with continued warming.  Spreading disease (i.e. mosquito carrying)  Earlier spring arrival  Plant and animal range shifts and population changes  Coral reef bleaching  Downpours, heavy snowfalls, and flooding  Droughts and fires Fingerprints and harbingers of climate change

Impacts over the last 100 years

Indicators of Climate Change Fingerprints of climate change Stratosphere cooling Troposphere warming Ocean warming

MET Temperature trends   Troposphere (0 - ~ 10km)   Stratosphere (10 – 50 km)   Surface temperatures are warming – (Certain)   Middle troposphere is also warming (Very likely) – – Early satellite data showed some cooling, but now that seemed to be due to instrument error.   Upper atmosphere is cooling (Certain) – – Why cooling? More energy trapped in troposphere.

Fingerprints of climate change Increases in water vapor

MET Water vapor feedback   Recall how the water vapor feedback works – – Increase in temp – – Increase evaporation – – Increase in water vapor in atmosphere   Water vapor is a greenhouse gas – – Increase in greenhouse effect – – Further warming (positive feedback)   Current models suggest that the water vapor feedback is responsible for about the same amount of warming as warming from increases in CO 2.   The importance of this feedback is still being investigated.

MET Global mean surface temperatures have increased

` Svalbard, Norway (79N)

Arctic

MET   Increased risk of floods, potentially displacing tens of millions of people due to – –sea level rise and heavy rainfall events   Bangladesh is projected to lose about 17% of its land area with a sea level rise of one meter – – –very difficult to adapt due to lack of adaptive capacity Sea Level rise

MET Recent Sea Level Changes

MET Sea Levels have risen

Branching coralBrain coral Increase in coral bleaching events: due to warmer ocean temperatures

Extreme Weather Events are Projected to Increase Higher maximum temperatures; more hot days and heatwaves over nearly all land areas (very likely) Higher minimum temperatures; fewer cold days frost days and cold spells over nearly all land areas (very likely) more intense precipitation events over many areas (very likely) increased summer drying over most mid-latitude continental interiors and associated risk of drought (likely) increase in tropical cyclone peak wind intensity, mean and peak precipitation intensities (likely) Increased mortality in old people in urban areas Damage to crops Heat stress on livestock Extended range of pests and diseases Loss of some crop/fruit Land slides, mudslides, damage to property and increased insurance costs Reduced rangeland productivity, increased wildfires, decreased hydropower Damage to various ecological and socioeconomic systems Projected changes during the 21st century Examples of impacts

Future impacts due to climate change

MET More adverse than beneficial impacts on biological and socioeconomic systems are projected

MET As a result of warming, plant species would be expected to migrate 1.North in the Southern Hemisphere 2.North in the Northern Hemisphere 3.South in the Northern Hemisphere 4.South in the Southern Hemisphere 5.To higher altitudes 6.To lower altitudes 7.1 and and 5

Where would you expect to see the strongest evidence of climate change? 1.Tropical latitudes 2.Midlatitude deserts 3.Midlatitude oceans 4.High latitudes 5.High altitude mountains

If ice melt was to stop even though average temperatures continue to warm, how would sea level respond 1.Sea level would continue to rise 2.Sea level would reach an equilibrium 3.Sea level would decrease

MET   Water availability – –Increase in some in some water-scarce regions, – –Decrease in many water scarce regions – –Globally, fresh water become more scarce   Increased agricultural productivity in some mid- latitude regions; reduction in the tropics and sub- tropics – –Overall impact is negative Impacts on water and agriculture

MET Effect on human health   Reduced winter mortality in – –mid- and high-latitudes   Increased incidence of heat stress mortality – –Tropics and midlatitudes   Increased incidence diseases in the tropics and sub-tropics – –such as malaria and – –water-borne diseases such as cholera,

MET Developing countries are the most vulnerable to climate change  Impacts are worse – –already more flood and drought prone –large share of the economy is in climate sensitive sectors  Lower capacity to adapt –because of a lack of financial and technological capacity  Climate change is likely to impact disproportionately upon the poorest countries and the poorest persons within countries,

MET Climate Change and California II Average Temperature: Winter - Summer – 1. 1.Coastal cities: 2. 2.Human health: 3. 3.Water resources: 4. 4.Agriculture:

MET Report Issued in 2004   Sections include: – –Climate projections – –Sea levels – –Extreme heat – –Health impacts – –Water resource – –Agriculture and vegetation

MET Climate change and California Average Temperature: Winter - warmer winters - snowpack declines by 70-90% by 2090 Summer – warmer summers (5-15F by 2090) 1. 1.Coastal cities: coastal erosion by sea level rise Human health: Urban air pollution/heat extremes impact most vulnerable 3. 3.Water resources: Total water, but early runoff from Sierras costly to adapt Agriculture: Major challenge to various crops industries.

MET Weather-related economic damages have increased

MET Hot Times in Alaska movie