Current and Future Trends and Impacts

© 2011 Pearson Education, Inc.

Current and Future Trends and Impacts

AP Environmental Science

Mr. GrantLesson 50


Objectives:

• Define the term Intergovernmental Panel on Climate Change (IPCC).

• Outline current and future trends and impacts of global climate change.


Intergovernmental Panel on Climate Change (IPCC): An international panel of climate scientists and government officials established in 1988by the United Nations Environment Programme and the World Meteorological Organization. The IPCC’s mission is to assess and synthesize scientific research on global climate change and to offer guidance to the world’s policymakers. The IPCC’s Fourth Assessment Report summarizes current and projected future global trends in climate, and represents the consensus of climate scientists around the world.

Define the term Intergovernmental Panel on Climate Change (IPCC).


Outline current and future trends and impacts of global climate change.

• The Intergovernmental Panel on Climate Change (IPCC) synthesizes current climate research, and its periodic reports represent the consensus of the scientific community.

• Temperatures on the Earth have warmed by an average of 0.74 degrees C (1.33 degrees F) over the past century and are predicted to rise 1.8-4.0 degrees C (3.2-7.2 degrees F) over the next century.

• Changes in precipitation vary by region.• Melting glaciers will diminish water supplies, and

melting ice sheets will add to sea level rise.


Outline current and future trends and impacts of global climate change.

• Sea level has risen an average of 17cm (7in) over the past century.

• Other impacts include ocean acidification; extreme weather events; effects on organisms and ecosystems; and impacts on agriculture, forestry and health, and economics.

• Climate change and its impacts will vary regionally.• Despite some remaining uncertainties, the scientific

community feels that evidence for human’s role in influencing climate is strong enough to justify taking action to reduce greenhouse emissions.


The IPCC’s fourth assessment report (2007)

• The IPCC reports on the synthesis of scientific information concerning climate change- Global consensus of scientific climate research- Summarized thousands of studies

• Documented observed trends in surface temperature, precipitation patterns, snow and ice cover, sea levels, storm intensity, etc.

• Predicted impacts of current and future climate change on wildlife, ecosystems, and human societies

• Discussed strategies to pursue in response to climate change


The IPCC’s fourth assessment report (2007)


Temperatures continue to increase• Average surface temperatures increased 0.74 °C since

1906- Most of the increase occurred in the last few decades- Extremely hot days have increased- The 16 warmest years on record have been since 1990


The future will be hotter

• In the next 20 years, temperatures will rise 0.4 °C• At the end of the 21st century, temperatures will be 1.8–

4.0 °C higher than today’s- We will have unusually hot days and heat waves

• Polar areas will have the most intense warming• Sea surface temperatures will rise• Hurricanes and tropical storms will increase

- In power and duration


Temperatures will rise globally

Projected increases in surface temperature for 2090–2099 relative to 1980–1999


Precipitation is changing, too

• Some regions are receiving more precipitation than usual, and others are receiving less

• Droughts have become more frequent and severe- Harming agriculture, promoting soil erosion,

reducing water supplies, and triggering fires• Heavy rains contribute to flooding

- Killing people, destroying homes, and inflicting billions of dollars in damage


Projected changes in precipitation

Precipitation will increase at high latitudes and decrease at low and middle latitudes


Melting snow and ice• Mountaintop glaciers are disappearing

- Glaciers on tropical mountaintops have disappeared- The remaining 26 of 150 glaciers in Glacier National

Park will be gone by 2020 or 2030- Reducing summertime water supplies

• Melting of Greenland’s Arctic ice sheet is accelerating• Warmer water is melting Antarctic coastal ice shelves

- Interior snow is increasing due to more precipitation• Melting ice exposes darker, less-reflective surfaces,

which absorb more sunlight, causing more melting


Worldwide, glaciers are melting rapidly• Nations are rushing to exploit underwater oil and mineral

resources made available by newly opened shipping lanes• Permafrost (permanently frozen ground) is thawing

- Destabilizing soil, buildings, etc. and releasing methane


Rising sea levels• Runoff from melting glaciers and ice will cause sea

levels to rise • As oceans warm, they expand

- Leading to beach erosion, coastal floods, and intrusion of salt water into aquifers


Coastal areas will flood

• Storm surge = temporary, localized rise in sea level- Caused by the high tides and winds of storms

• Cities will be flooded- 53% of people in the U.S. live in coastal areas

An earthquake caused the 2004 tsunami (tidal wave) that killed 100 Maldives residents and caused $470 million in damages


Rising sea levels will devastate coasts• 1 million acres of Louisiana’s wetlands are gone

- Rising sea levels eat away vegetation- Dams upriver decrease siltation- Pollution from the Deepwater Horizon

• Millions of people will be displaced from coastal areas


Coral reefs are threatened

• Coral reefs are habitat for food fish - Snorkeling and scuba diving sites for tourism

• Warmer waters contribute to coral bleaching- Which kills corals

• Increased CO2 is acidifying the ocean- Organisms can’t build their exoskeletons

• Oceans have already decreased by 0.1 pH unit- Enough to kill most coral reefs


Climate change affects organisms and ecosystems• Organisms are adapted to their environments

- They are affected when those environments change• Global warming modifies temperature-dependent

phenomena (e.g., timing of migration, breeding)• Animals and plants will move toward the poles or

upward in elevation- 20–30% of species will be threatened with extinction- Rare species will be pushed out of preserves

• Droughts, fire, and disease will decrease plant growth- Fewer plants means more CO2 in the atmosphere


Animals and plants have nowhere to go

• Animals and plants adopted to montane environments will be forced uphill until there is no place to go


Climate change affects people

• Societies are feeling the impacts of climate change• Agriculture: shortened growing seasons, decreased

production, crops more susceptible to droughts - Increasing hunger

• Forestry: increased fires, invasive species- Insect and disease outbreaks

• Health: heat waves and stress can cause death- Respiratory ailments, expansion of tropical diseases- Disease and sanitation problems from flooding- Drowning from storms


Heat waves will increase


Climate change affects economics

• Costs will outweigh benefits of climate change• It will widen the gap between rich and poor

- Those with less wealth and technology will suffer most• External costs of damages will be $10–350/ton of carbon• It will cost 1–5% GDP on average globally

- Poor nations will lose more than rich ones• The Stern Review predicts it will cost 5–20% of GDP by

2200- Investing 1% of GDP now could avoid these costs


Impacts will vary regionally• Where we live will determine how we experience the

impacts of climate change• Temperature changes have been greatest in the Arctic

- Melting ice sheets, thinning ice, increasing storms, etc.- Harder for people and polar bears to hunt

• U.S. temperatures will continue rising- Plant communities will shift north and upward- More frequent extreme weather events

• The southern U.S. will get drier, the northern wetter- Sea levels will rise and may be worse in the East


Impacts of climate change

The Arctic has suffered the most so far

U.S. temperatures will continue to rise


Impacts of climate change will vary


The U.S. Global Change Research Program• In 2009, scientists reported and predicted:

- Temperature increases - Worse droughts and flooding- Decreased crop yields- Water shortages- Health problems and diseases- Higher sea levels, beach erosion, destroyed wetlands- Drought, fire, and pests will change forests- More grasslands and deserts, fewer forests- Undermined Alaskan buildings and roads


Predictions from two climate models

By 2050, Illinois will have a climate like Missouri’s

By 2090, it will have a climate like Louisiana’s


Causes and consequences of climate change


Are we responsible for climate change?• Scientists agree that increased greenhouse gases are

causing global warming- Burning fossil fuels is increasing greenhouse gases

• In 2005, scientists from 11 nations issued a joint statement urging political leaders to take action

• There is a broad and clear scientific consensus that climate change is a pressing issue- But many people deny what is happening

• People will admit the climate is changing- But doubt we are the cause


The debate over climate change is over

• Conservative think tanks and industry-sponsored scientists cast doubt on the scientific consensus

• The news media tries to present two sides to an issue- But the sides’ arguments are not equally supported by

evidence• Most Americans accept that fossil fuel consumption is

changing the planet• Al Gore’s An Inconvenient Truth helped turn the tide

- People who disliked his politics rejected his message


“Climategate”

• In 2009, a hacker illegally broke into a university’s computer in the U.K.

• Private emails seemed to show questionable behavior by a few scientists in using data

• Climate deniers accused the entire scientific establishment of wrongdoing and conspiracy- The story was widely told in the news

• Investigations showed no evidence of wrongdoing- Media accounts misrepresented the email contents

• These hacked emails do not call into question the vast array of results by thousands of scientists over decades

Documents

Current and Future Trends and Impacts