Greenhouse Gases and Climate Change Greenhouse Effect Natural

Greenhouse Gases and Climate Change

Greenhouse Effect • Natural Greenhouse Effect makes life on Earth possible • As levels of GHG (greenhouse gases) increase, potential for climate change increases. – GHG concentration fluctuates naturally – GHG concentration altered by human activity

Water Vapor • Most important atmospheric GHG because it controls life on Earth via water cycle • Does not appear to be changing in concentration • Increased water vapor could increase cloud cover lead to cooling • Increased water vapor could increase heat holding high, thin cirrus clouds lead to heating

Carbon Dioxide • Naturally produced during respiration and decomposition. – This is balanced by amount absorbed by photosynthesis and diffusion into sea water • CO 2 levels were relatively stable for 10, 000 years before Industrial Revolution. – Steady increase in CO 2 since introduction of combustion of fossil fuels – Deforestation also increases CO 2 levels

Methane (CH 4) • 23 x more powerful GHG as compared to CO 2 • Naturally produced during decomposition – Specifically in marshes, swamps and rice paddies • Increased production of animals for consumption (cattle and sheep) increases methane production. • Increased waste production increases the methane production in landfills during decay.

CFC’s • Influence on climate change is small but because of their persistence, they will remain a GHG for the next 100 years

Nitrous Oxide (N 2 O) • 310 x more potent than CO 2 • 18% above naturally occurring levels • Results from – excess fertilizers – burning fossil fuels – Production of nylons (plastics)

Ozone • Helpful in stratosphere as Earth’s “sun screen” • GHG and air pollutant in troposphere