Tuesday, 26 February 2019

An increase in the average temperature of the Earth’s atmosphere and oceans Global temperature on both land and sea increased by 0.6 ± 0.2 °C over the past century Volume of atmospheric carbon dioxide increased from 280 parts per million in 1800 to 367 in 2000, a 31% increase over 200 years


Global Warming
 What is Global Warming?
An increase in the average temperature of the Earth’s atmosphere and oceans
Global temperature on both land and sea increased by 0.6 ± 0.2 °C over the past century
Volume of atmospheric carbon dioxide increased from 280 parts per million in 1800 to 367 in 2000, a 31% increase over 200 years


 Our Changing Climate
Global mean surface temperatures have increased 0.5-1.0°F since the late 19th century
The snow cover in the Northern Hemisphere and floating ice in the Arctic Ocean have decreased
Sea level has risen 4-8 inches over the past century
Global surface temp. could rise 1-4.5°F (0.6-2.5°C) in the next fifty years, and 2.2-10°F (1.4-5.8°C) in the next century

 What causes it?
Human Impacts- Atmospheric greenhouse gases trap some of the outgoing energy, retaining heat
Natural Impacts- Change in sun’s energy output Volcanoes Water Vapor Clouds

Greenhouse Gases -
CO2 Methane Nitrous oxide Fluorinated compounds
Since industrial revolution, atmospheric concentrations of carbon dioxide increased 30%, methane more than doubled, nitrous oxide risen by 15%.
These increases have enhanced the heat-trapping capability of the earth’s atmosphere
Greenhouse Gas Emissions

  • Combustion of fossil fuels? coal-burning power plants, automobile exhausts, factory smokestacks, other waste vents of the human environment contribute 22 billion tons of carbon dioxide and other greenhouse gases each year
  • Animal agriculture, manure, natural gas, rice paddies, landfills, coal, and other anthropogenic sources contribute about 450 million tons of methane each year
  • Atmospheric concentrations of CO2 and CH4 have increased by 31% and 149% respectively above pre-industrial levels since 1750


 Greenhouse Gas Emissions
Power Plants 
40% of carbon dioxide emissions stem from the burning of fossil fuels for the purpose of electricity generation
Cars 
20% of carbon dioxide emissions comes from the burning of gasoline in internal-combustion engines of cars and light trucks with poor gas mileage contribute the most to global warming
Trucks 
Another 13% of carbon dioxide emissions come from trucks used mostly for commercial purposes
Airplanes 
Aviation causes 3.5 percent of global warming, and the figure could rise to 15 percent by 2050
Carbon Dioxide from Buildings 
Buildings structure account for about 12% of carbon dioxide emissions
Methane
Methane is more than 20 times as effective as CO2 at trapping heat in the atmosphere 2004 Levels of atmospheric methane have risen 145% in the last 100 years
Derived from sources such as rice paddies, bovine flatulence, bacteria in bogs and fossil fuel production . In flooded fields, anaerobic conditions develop and the organic matter in the soil decomposes
Nitrous oxide 
Naturally produced by oceans and rainforests , man-made sources-nylon and nitric acid production, the use of fertilizers in agriculture, cars with catalytic converters and the burning of organic matter
Deforestation
Responsible for 25% of all carbon emissions entering the atmosphere by the burning and cutting of about 34 million acres of trees each year .


 The Carbon Cycle


 Effects of Global Warming
Negative Effects

Rising Sea Level
Change of precipitation and local climate conditions; acid rain
Alteration of forests and crop yields
Expansions of deserts into existing rangelands
More intense rainstorms
Destabilization of Ocean currents

Positive Effects

Can stimulate plant growth in places where CO2 and temperature are the limiting factors (preventing photorespiration which can destroy existing sugars).
Melting Arctic ice may open the Northwest Passage in summer, which would cut 5,000 nautical miles from shipping routes between Europe and Asia

 What Can be Done: Alternatives
Renewable Energy Sources
Solar EnergiesWind PowerBiomassGeothermal

HybridFuel CellBattery-Electric
Kyoto Protocol
  • 1997, Kyoto, Japan ? developed countries agreed to specific targets for cutting their emissions of greenhouse gases
  • Industrialized countries committed to an overall reduction of emissions of greenhouse gases to 5.2% below 1990 levels for the period 2008 - 2012
  • Objective is the stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system
 References
Choi, O. and A. Fisher (2003) "The Impacts of Socioeconomic Development and Climate Change on Severe Weather Catastrophe Losses: Mid-Atlantic Region (MAR) and the U.S." Climate Change, vol. 58 pp. 149
  • Dyurgerov, Mark B, Mark F. Meier (2005). Glaciers and the Changing Earth System: a 2004 Snapshot, Institute of Arctic and Alpine Research, Occasional Paper
  • Climate Change and Global, Anup Shah, Global Issues, Warming http://www.globalissues.org/EnvIssues/GlobalWarming.asp
  • The Carbon Cycle & the Greenhouse Effect, Corresponding Readings in Primack, Richard B. http://www-personal.umich.edu/~dallan/nre220/outline20.htm
  • The Effects of Global Warming, http://www.geocities.com/TimesSquare/1848/global.html
  • Evidence of Global Warming, http://www.ecobridge.org/content/g_evd.htm
  • The impact of global warming in Asia, http://www.climatehotmap.org/asia.html

No comments:

Post a Comment