Climate Change and Ozone Loss Chapter 18 “We are embarked on the most colossal ecological experiment of all time – doubling the concentration in the atmosphere of an entire planet of one of its most important gases – and we really have little idea of what might happen.” Paul A. Colinvaux

Key Concepts How does the Earth’s climate fluctuate What factors affect climate What are the possible effects of global warming What can humans do about potential climate change How are human activities affecting the ozone layer What can humans do about changes in the ozone layer

Past Climate Change Past global temperatures Recent trends in global temperatures Fig pg 447

The Natural Greenhouse Effect Greenhouse effect Greenhouse Gases

Climate Change and Human Activities Increased use of fossil fuels Deforestation Global warming Melting icecaps and glaciers Coral reef bleaching

Projecting Future Changes in Earth’s Climate Climate models (see Spotlight p 457) Apparent influence of human activities Could be natural changes Fig p. 455

Factors Affecting Changes in Earth’s Average Temperature Changes in solar output Changes in Earth’s albedo Moderating effect of oceans Clouds and water vapor Air pollution Fig p 458

Some Possible Effects of a Warmer World Fig p 461

Solutions: Dealing with the Threat of Climate Change Do nothing Do more research Act now to reduce risks No-regrets strategy Options: Fig p 466

Removing CO 2 From The Atmosphere Tree plantation Coal power plant Tanker delivers CO 2 from plant to rig Oil rig Crop fieldSwitchgrass field Spent oil reservoir is used for CO 2 deposit CO 2 is pumped down to reservoir through abandoned oil field Abandoned oil field CO 2 is pumped down from rig for Deep ocean disposal = CO 2 deposit = CO 2 pumping Fig p 467

Reducing Greenhouse Gas Emissions Rio Earth Summit (1992) Kyoto Treaty (1997) Some US CO 2 Reductions

Ozone Depletion in the Stratosphere Fig , p 473 Terrestrial life Reduce sunburn Prevents tropospheric ozone Importance of Ozone

Ozone Depleting Chemicals Chlorofluorocarbons (CFC’s) Halons Methyl bromide Carbon tetrachloride Methyl chloroform Hydrogen chloride

Seasonal Thinning at the Poles Ozone thinning (hole) Fig pg. 475 Polar vortex

Reasons for Concern Increased incidence and severity of sunburn Increase in eye cataracts Increased incidence of skin cancer Immune system suppression Increase in acid deposition Lower crop yield and decline in productivity

Solutions: Protecting the Ozone Layer CFC substitutes Technofixes Montreal Protocol Fig pg. 479