| Popis: |
The Earth receives a large amount of radiant energy from the sun and about 30% of this energy is reflected. The longer wave infrared radiation does not penetrate back through the atmosphere as efficiently as did the incident radiation. The reflected heat is absorbed by water vapor and carbon dioxide thereby warming the Earth. Anthropogenic activities result in increased atmospheric levels of carbon dioxide (CO2), methane (CH4), ozone (O3), sulfur dioxide (SO2), chlorofluorocarbon (CFC) and nitrogen dioxide (NO2), collectively known as greenhouse gases, causing the Earth to grow warmer. The consequences of the greenhouse effect are evidenced in the rising records of global temperature and atmospheric CO2. Over the past 150 years, atmospheric CO2 concentrations have risen from ∼270 ppm to over 415 ppm today. Resulting changes in carbon chemistry, precipitation, and temperature will lead to largescale adjustments in the distribution of vegetation, global net primary production, agricultural productivity, ocean acidification, ocean warming, and sea level rise. |
