Climate Change Ecosystems

Slide1: 

Peter H. Hildebrand, Ph.D. Climate Change and Ecosystems Hydrospheric and Biospheric Sciences Laboratory NASA Goddard Space Flight Center, Greenbelt, MD

Slide2: 

Climate, Water and Life on Earth Earth’s climate: natural and human forces of change Earth’s water cycle in a changing climate Ecosystem impacts Actions we can take

Slide3: 

100 100 Incoming Solar Radiation Outgoing Earth Radiation Earth’s Heat Budget Incoming and outgoing radiation must balance The atmosphere, clouds, and greenhouse gases keep us warm.

Greenhouse Gas and Human Activity: 

Greenhouse gases are natural: H2O, CO2, CH4, . . . Humans add more greenhouse gases These gases are warming the Earth Greenhouse Gas and Human Activity

How do we know about Greenhouse Gases?: 

How do we know about Greenhouse Gases? Greenhouse gas concept known since 1820s: Joseph Fourier (1824, 1927) John Tyndall (1861) Svante Arrhenius (1896) David Keeling measured CO2 on top of Mauna Loa CO2 is increasing each year winter summer High CO2 values = northern winter Low CO2 values = northern summer, (when trees are growing)

Radiative Forcing of Climate Change: 

Radiative Forcing of Climate Change Climate Change Forcing in the Industrial Era (1850-2000) ► CO2 Is Largest Forcing ► Air Pollutants (O3, CH4, BC) Cause Large Forcing ► Aerosol Effects (direct + on clouds) Most Uncertain Conclusion: CO2 Largest Forcing, But Others Significant References: ►Trends of measured climate forcing agents, Proc.Natl.Acad.Sci., 98, 14778, 2001. ►Efficacy of climate forcings, J. Geophys. Res., in press, 2005.

Slide7: 

Climate Variability: Global Temperature

How do we know about greenhouse gas history?Climate records from polar ice cores: 

The history of Earth climate is available from Antarctic and Greenland ice cores. Temperatures from oxygen isotope ratios. Greenhouse gases from air bubbles trapped in the ice cores. Other measurements validate these records. How do we know about greenhouse gas history? Climate records from polar ice cores

Climate Change: variability over 450,000 years: 

Climate Change: variability over 450,000 years Ice Ages (cold, dry, windy) Warm periods (warm, wet, calm) greenhouse gases change in response to climate change Last 150yrs: greenhouse gases driving temperature change

The Water Cycle and Climate: 

Terrestrial water cycle Precipitation Storm and drought intensity Snowfall Runoff Tropical storms Global ice Ice sheets and glaciers / sea ice Sea level The Water Cycle and Climate As the Earth has warmed, what has happened to Earth’s water resources ?

Slide11: 

Where has the Earth warmed? Hotter Equator

Changes in Precipitation: 

Changes in Precipitation Less Rain More Rain

Precipitation Intensity Increases: 

Precipitation Intensity Increases More days with precipitation More frequent and intense precipitation Precipitation increases are due to the strong events

Snow Cover Reduced: 

Snow Cover Reduced As temperatures increase: Snow cover reduced 1-2 days/yr since early 1970’s Water storage in snow pack is reduced More precipitation is rain Snow onset is later Melt is earlier

Slide15: 

days/yr The Water Cycle and Climate Runoff Changes With a warmer land and atmosphere: Runoff changes: More precipitation falls as rain Winter runoff is increased Winter starts later & ends earlier Spring runoff pulse is earlier Summer runoff is decreased

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Tropical Storms Orange colors indicate where SST’s will support Tropical Cyclone Development SST ≥ 82°F

Hurricane Intensity Increases: 

Hurricane Intensity Increases Hurricane intensity changes: fewer category 1 storms more cat 4 and 5 storms Sea surface temperatures are increasing globally

Polar Ice Sheets: 

Polar Ice Sheets Changes in polar ice: Ice sheets Sea ice Ecosystem impacts Sea level impacts

Antarctica: Melting and Thickening: 

Antarctica: Melting and Thickening Thickening due to increased precipitation Melting around the edges

Greenland: Melting: 

Greenland: Melting

The Water Cycle and Climate: 

Precipitation: More & Heavier events Storm intensity Stronger large scale weather patterns: More intense heavy precipitation & drought More intense storms including hurricanes Snowfall decrease Later freeze, earlier thaw More precipitation as rain Earlier runoff Melting of ice sheets and glaciers Sea level rise The Water Cycle and Climate With a hotter Earth, what has happened to water resources?

Ecosystem Impacts:Melting Ice in the Arctic: 

Ecosystem Impacts: Melting Ice in the Arctic

Ecosystem Impacts: What does this mean for a farmer?: 

Ecosystem Impacts: What does this mean for a farmer? He is concerned about climate change effects: Getting enough water from the river (snow melt) for irrigation Getting water in the summer Reservoir management Urban encroachment

Climat Change and the Water Cycle Why are scientists concerned?: 

The Earth system is replete with tipping points: small changes that cause big effects Climat Change and the Water Cycle Why are scientists concerned? Examples of Causes and effects: Earth orbit variability  ice-age climate cycle Arctic Melting  Ocean circulation slows

Tipping Points: Ice Ages vs. Interglacial Periods: 

Tipping Points: Ice Ages vs. Interglacial Periods Ice Ages (cold, dry, windy) Warm periods (warm, wet, calm) greenhouse gases change in response to climate change Last 150yrs: greenhouse gases driving temperature change

Climate over the past 450,000 years:Ice ages, brief warm spells, & lots of variability: 

Climate over the past 450,000 years: Ice ages, brief warm spells, & lots of variability Earth-sun orbital cycles (causative): eccentricity, precession, nutation Earth circulation variability (causative): E.g. el Niño; also, longer scale major variability Greenhouse gases: were in reaction to Earth circulation / temperature changes now a causative factor What makes the climate change?

Tipping Points: Polar Melting & Global Heat Transport: 

Global warming feedback loop: Reduced snow/ice cover albedo is reduced solar heating is increased tundra & permafrost thaw more greenhouse gases released Melted ice sheets release fresh water into ocean fresh water dilutes cold salty North Atlantic water shuts down the North Atlantic circulation this changes global heat transport This climate “switch” has been thrown many times! Tipping Points: Polar Melting & Global Heat Transport

Slide28: 

Climate models are now pretty good. A major uncertainty is: What are we humans going to do? IPCC “Emissions Scenarios” A2: heterogeneous world, continued population growth A1B: rapid economic growth, homogeneous world, population peaks ~2050, mixed fossil/non-fossil fuel use B1: =A1 with global sustainability and equity focus Climate Forecasting

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Climate Forecasting more less People, Development & Pollution

Slide30: 

Climate Change and Societal Decisions

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Climate Change and Societal Decisions Society can make choices that will affect our environment Present averaged heating due to greenhouse gases Possible future heating: need to limit the amount of heating

What can we do?Change how we live: reduce energy use emphasize sustainability reduce population growthChange our technology: improve energy use efficiency: 

What can we do? Change how we live: reduce energy use emphasize sustainability reduce population growth Change our technology: improve energy use efficiency

Thank you!: 

Thank you! For more information please visit http://neptune.gsfc.nasa.gov/

The Water Cycle and Climate Human water use 1900 – 2000 : 

The Water Cycle and Climate Human water use 1900 – 2000

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The Water Cycle and Climate Human water use: Grain Production

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Grain Production

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For more information Books: Richard Alley: The Two–Mile Time Machine. A very readable climate change book for the lay reader written by a noted Penn State Prof.  Brian Fagen: The Long Summer. A discussion of how the warming at the end of the last ice age fostered the development of human civilization. Jared Diamond: Collapse. As Diamond says: how societies choose to fail or succeed. Malcolm Gladwell: The Tipping Point. A discussion of how small factors can sometimes result in large changes. Web Resources: Climate science web site: www.realclimate.org US Global Change Research Program: www.usgcrp.gov UN Environmental Program: www.unep.org NASA Earth Sciences: earthsciences.gsfc.nasa.gov Goddard Hydrospheric & Biospheric Sciences: neptune.gsfc.nasa.gov NASA Goddard Climate Sciences: www.giss.nasa.gov Climate change figures: www.grida.no/climate/vital/index.htm USDA Foreign Agricultural Service: www.fas.usda.gov/grain/circular/2004/05-04/graintoc.htm Worldwatch: www.worldwatch.org Climate, Water and Life on Earth Peter H. Hildebrand, Ph.D., NASA Goddard

Climate Change and Desertification : 

Climate Change and Desertification NDVI = (ir- red) (ir+red) NDVI measures plant greenness The Sahel Movement with climate change

How might warming affect the global water cycle?: 

How might warming affect the global water cycle? 38 38 105 67 393 355 1000 km3/yr