climate change
TRANSCRIPT
What is Climate Change? ‘‘It is a change which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparative time periods”
GREENHOUSE GASES such as carbon dioxide (CO2) absorb heat (infrared radiation) emitted from Earth’s surface. Increases in the atmospheric concentrations of thesegases cause Earth to warm by trapping more of this heat.
Human activities—especially the burning of fossil fuels since the start of the Industrial Revolution—have increased atmospheric CO2 concentrations by about 40%, with more than half the increase occurring since 1970. Since 1900, the global average surface temperature has increased by about 0.8 °C (1.4 °F). This has been accompanied by warming of the ocean, a rise in sea level, a strong decline in Arctic sea ice, and many other associated climate effects.
CAUSESNATURAL CAUSES
Volcanic Eruptions. Emissions of methane from animal wastes, a
greenhouse gas. Earth naturally has a cycle of climate change
that occurs every 40, 000 years. the sun’s solar energy output is changing and
naturally increases Earth’s average temperature by about 1ºC every century.
Earth’s orbit and tilt alter in relation to the sun, which changes solar energy output.
CAUSESHUMAN CAUSES
Greenhouse gases Deforestation Coal mining Burning of fossil fuels Industrial processes Agriculture Over-population
EFFECTS Rise in Sea level. Heavy Rainfall. Extreme Drought. Decline in Crop Productivity. Ecosystems are changing. Rise in Temperature. Carbon dioxide acidifies sea water. Damaged crops due to sudden climate change
and floods. Longer summers can disrupt animal habitation. Increased number of heat-related illnesses
and deaths.
DEALING w i t h G l o b a l C l i m a t e C h a n g e
To avoid the worst of climate change, CO2 levels must be stabilized at 550ppm
50% higher than current levels
-Two ways to attempt to manage climate change Mitigation
Focuses on limiting greenhouse gas emissions to moderate global climate change
Adaptation Focuses on learning to live with to the environmental changes and societal consequences brought about by global climate change
Mitigation
Locate/invent alternative fuels to fossil fuels.
Increase efficiency of cars and trucks.
Sequestering carbon before it is emitted.
Plant and Maintain trees to naturally sequester carbon.
Adaptation
Rising sea levels and coastal populations:
-Move inland -Construct dikes and levees
Adapt to shifting agricultural zones
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