HUMAN IMPACT I PP. 435-444

EARTH’S LAYERS

Hydrosphere: includes oceans, lakes, rivers, and water vapor Atmosphere: mixture of gases surrounding the planet Geosphere: rock interior including ocean floor Biosphere: part of the earth where life (biota) exists

GREENHOUSE EFFECT (good) When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases The ability of our atmosphere to trap heat keeps our planet warm and habitable

GLOBAL WARMING (bad)

Excess CO2 and water vapor released from burning of fossil fuels adds to the “greenhouse” trapping more heat Correlation between temperature and CO2 levels Positive feedback is now driving global warming. The warming increases the amount of water vapor in the atmosphere, which in turn leads to further warming, which increases water vapor, and so on.

CLIMATE CHANGE (bad)

Excess carbon dioxide can lead to climate change and many species are sensitive to even small changes in the climate and temperature EX. Gender in amphibians is due to one gene not a whole chromosome. This gene can be influenced by even a small change in temperature.

OCEAN ACIDIFICATION Excess carbon dioxide gas is absorbed by the ocean and reacts with seawater to change the pH causing ocean acidification and preventing calcification of marine organisms Many of these organisms are lower on the food chain that support the higher trophic levels

ACID RAIN Burning of coal produces H2SO4 (sulfuric acid) and burning of gasoline produces HNO3 (nitric acid) These pollutants enter the atmosphere to form acidic water (acid rain) Some bodies of water can buffer the effects of acid rain Animals and plants sensitive to pH changes suffer the most

HOLE IN THE OZONE LAYER O3 (ozone) makes up the ozone in the upper atmosphere and blocks radiation CFCs from refrigerators and propellants break down ozone Localized in southern hemisphere and increases in size over time (especially OCT)