20 Global Climate Change

Climate Change Terminology

Greenhouse Gas Gas that absorbs infrared radiation

Positive Feedback Loop Change in some condition triggers a response that intensifies the

changed condition

Infrared Radiation Radiation that has a wavelength that is longer than that of visible

light, but shorter than that of radio waves

Greenhouse Effect Increase of heat in a system where energy enters (often as light),

is absorbed as heat, and released sometime later

Climate Change (not global warming)

Refers to the recent and ongoing rise in global average temperature near Earth's surface caused (mostly) by increasing concentrations of

greenhouse gases in the atm. significant change in climate lasting for an extended

period of time includes major changes in:

Temperature Precipitation Wind patterns Occurring over several decades or longer

Greenhouse gases

Greenhouse gases act like a blanket around Earth, trapping energy in the atmosphere and causing it to warm

Increased concentration of CO2

Burning fossil fuels in cars, industry and homes Deforestation Burning of forests Industrialization

This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Source: NOAA)

Greenhouse

EffectWhat we know

CO2 accounts for 60% of increased

heat retention

Radiative Forces

Capacity of gas to affect energy

entering and leaving the atm

Introduction to Climate Change

Certain facts about climate are not in dispute

What we Know CO2 has the ability to trap heat Methane, Nitrous oxides, CFC’s tropospheric ozone can

also trap heat demonstrated in the mid-19th century CO2 ability to capture infrared energy scientific basis of many

instruments flown by NASA Based on the knowledge above the following can be assumed

Increased levels of greenhouse gases must cause the Earth to warm in response

What we know

Sea level rise Last 100 years rose ~6.7 inches Last 10 years, rose ~12 inches

Global temperature rise All major global surface temp reconstructions show that

Earth has warmed since 1880. Most of this warming has occurred since the 1970s the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the

past 12 years

What we knowSciences evidence

Warming oceans Oceans have absorbed much of this increased heat,

with the top 2,300 feet of ocean showing warming of 0.3020F since 1969

Shrinking ice sheets Greenland & Antarctic ice sheets have decreased Data from NASA's show

Greenland lost 36-60 cubic miles of ice/year from 2002 - 2006 Antarctica lost 36 cubic miles of ice/year 2002-2005.

Declining Arctic sea ice / Glacial retreat / Extreme events / Ocean acidification

Pollutants That Cool the Atmosphere

Atmospheric Aerosols - “ Aerosol Effect” Both human and natural sources Sulfur can remain in troposphere for weeks or months Sulfur-laden haze in the atm reflects infrared radiation

Complicates models of climate change Negative feedback loop

occurs when the result of a process influences the operation of the process itself in such a way as to reduce changes

One of the many complications that affects modeling climate change

Climate Models

Climate affected by: winds, clouds & ocean currents

Advanced models can project future warming events Do there best to factor in all known data

Models are only as good as the data Models have limitations

Effects of Global Climate Change - Melting Ice & Rising Sea Levels

IPCC – International Panel on Climate Change Projects sea-level rise of 18-59 cm by 2100 Projects temp to rise1.8 to 4.0ºC by 210

Sea level rise - 2 ways Thermal Expansion

matter changes in volume in response to a change in temp Melting of land ice

Melting has positive feedback Increased melting decreases ice, which decreases

albedo leading to further warming(Albedo – Reflections from the a white surface)

Melting Ice & Rising Sea Levels

Thermal expansion When water heats up, it expands

Melting of glaciers and polar ice caps Large ice formations, like glaciers and the polar ice caps, naturally melt

back a bit each summer.

Melting of surface ice massive ice sheets that cover Greenland and Antarctica to melt at an

accelerated pace

Consequences Seawater reaches farther inland destructive erosion, flooding of wetlands, contamination of aquifers &

agricultural soils lost habitat for fish, birds, and plants

Case-In-Point Impacts in Fragile Areas

Eskimo Inuit live traditional life Alaska & Canada Dictated by freezing climate

Climate change is altering their existence Wildlife displaced Reduced snow cover & shorter ice seasons Thawing of permafrost

soil at or below the freezing World-wide, permafrost contains huge amounts of dissolved carbon

The amount of carbon sequestered in permafrost is 4x the carbon that has been released to the atmosphere due to human activities in modern time

Effects of Global Climate Change- Changing Precipitation Patterns

Some areas will get more water, some areas will have greater droughts

Effects on Organisms - Coral Reefs

Coral reefs can be bleached due to increase in water temperature & increase in pH (Acidic) Affects coral symbiotes & makes them more susceptible

to diseases

Effects of Global Climate Change- Effects on Organisms

Zooplankton in parts of California Current have decreased by 80% since 1951 Affecting entire food chain

Species have shifted their geographic range

Migrating birds are returning to summer homes earlier

Ecosystems at greatest risk of species loss coral reefs, mountain ecosystems, coastal wetlands,

tundra, and polar spas

Effect on Organisms - Vegetation

Effects on Agriculture

Difficult to anticipate Productivity may increase in some areas & decrease in

others Rise in sea level will inundate flood plains & river

valleys

Effect on pests is unknown

Warmer temperatures will decrease soil moisture - requiring more irrigation

Location where certain crops can be grown may have to change

Effects of Global Climate Change

Extreme weather More Wildfire in California More extreme hurricanes

International Implications of Climate Change

Developed vs. Developing countries Differing self-interests Differing ability to meet the challenges of climate change

Dealing with Global Climate ChangeTwo ways to manage climate change

Mitigation: Limiting greenhouse gas emissions Locate/invent

alternative fuels to fossil fuels Increase efficiency of cars and trucks Carbon Capture and Storage Plant and Maintain trees to naturally sequester carbon

Adaptation: Learning to live with environmental changes & societal

consequences brought about by global climate change Move inland (Rising sea levels) Construct dikes and levees Adapt to shifting agricultural zones

Relationship Between Mitigation & Adaptation

International Efforts to Reduce Greenhouse Gas Emission

Kyoto Protocol Legally binding Provides operational rules on reducing greenhouse

gases By 2010, 183 countries had ratified it

US has not sign it. The reason being….. It did not require developing countries to make emission reductions

It would seriously harm the economy of the United States Clinton signed it but the senate and house did not

It will be difficult to implement without US backing EPA is taking it upon itself to define laws associated with CO2

reduction in US

Those that agree the climate is changing due to human influence 97% of Scientists

NASA EPA (Environment protection agency) – of course NIH (National Institute of Health)

Skeptics

Modeling system are flawed They do not take into account many factors Can not predict the future

Do not have enough good recorded temp data This could be just part of a large weather cycle that has

not recorded (We have not been around long enough to record temp over thousands of years)

Aren't temperature changes natural? Can't we wait and fix the climate if things get

really bad

Interesting things on-line

You tube: Climate change way over simplified (but very interesting to think about)

http://www.upworthy.com/one-guy-with-a-marker-just-made-the-global-warming-debate-completely-obsolete-7

As always know your source – all info is bias in one direction or the other. Do your best to get raw (not

manipulated) data.