MET 112

1

MET 112 Global Climate Change: Lecture 13

Climate Change Impacts: Present and Future II

Dr. Craig Clements

MET 112

2

Climate Change ImpactsClimate Change Impacts What signals would we expect from a warmer world?What signals would we expect from a warmer world?

– Higher average temperatureHigher average temperature– Higher maximum temperaturesHigher maximum temperatures– Higher minimum temperaturesHigher minimum temperatures– More precipitationMore precipitation– Higher sea levelHigher sea level

What ‘evidence’ do we have for changes in the 20th What ‘evidence’ do we have for changes in the 20th century?century?

MET 112

3

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 Fingerprints and harbingers of climate changeclimate change

MET 112

4

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 Fingerprints and harbingers of climate changeclimate change

Impacts over the last 100 yearsImpacts over the last 100 years

Indicators of

Climate Change

Fingerprints of climate change

Stratosphere cooling

Troposphere warming

Ocean warming

MET 112

7

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.

MET 112

9

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 CO2.

The importance of this feedback is still being investigated.

MET 112

10

Global mean surface temperatures have increased

`

Svalbard, Svalbard, Norway (79N)Norway (79N)

ArcticArctic

MET 112

13

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 112

14

Recent Sea Level Changes

Branching coral Brain coral

Increase in coral bleaching events: due to warmer ocean temperatures

http://www.climatehotmap.org/

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 Future impacts due to climate changeclimate change

MET 112

20

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

MET 112

21

As a result of warming, plant species would be expected to migrate1. North in the Southern Hemisphere2. North in the Northern Hemisphere3. South in the Northern Hemisphere4. South in the Southern Hemisphere5. To higher altitudes6. To lower altitudes7. 1 and 68. 2 and 5

Where would you expect to see the strongest evidence of climate change?1. Tropical latitudes2. Midlatitude deserts3. Midlatitude oceans4. High latitudes5. High altitude mountains

If ice melt was to stop even though average temperatures continue to warm, how would sea level respond1. Sea level would continue to rise2. Sea level would reach an equilibrium3. Sea level would decrease

MET 112

24

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 112

25

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 112

26

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 112

27

Climate Change and California IIAverage Temperature:

Winter -

Summer – 1. Coastal cities:

2. Human health:

3. Water resources:

4. Agriculture:

MET 112

28

Report Issued in 2004

Sections include:– Climate projections– Sea levels– Extreme heat– Health impacts– Water resource – Agriculture and

vegetation

MET 112

33

Climate change and CaliforniaAverage Temperature:

Winter - warmer winters - snowpack declines by 70-90% by 2090

Summer – warmer summers (5-15F by 2090)1. Coastal cities: coastal erosion by sea level rise.2. Human health: Urban air pollution/heat extremes

impact most vulnerable3. Water resources: Total water, but early runoff from

Sierras costly to adapt.4. Agriculture: Major challenge to various crops

industries.

MET 112

34

Weather-related economic damages have increased

MET 112

35

Hot Times in Alaska movie

http://www.pbs.org/saf/1404/video/watchonline.htm