SLIDE 3 Scientists around the world agree It is
Global Warming Global Warming defined
Global warming is the increase in the average measured temperature of the Earth's near-surface air and oceans since the mid- 20th century, and its projected continuation.
On Earth, the major greenhouse gases are
Water vapor, which causes about 36–70 percent of
the greenhouse effect (not including clouds);
- Carbon dioxide (CO2), which causes 9–26 percent;
Methane (CH4), which causes 4–9 percent; Methane (CH4), which causes 4 9 percent; And ozone, which causes 3–7 percent. Other greenhouse gases include, but are not limited
to, nitrous oxide, sulfur hexafluoride, hydro fluorocarbons, per fluorocarbons and chlorofluorocarbons.
Relation between Global Warming & Greenhouse Effect
The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid- twentieth century is very likely due to the observed twentieth century is very likely due to the observed increase in anthropogenic (man-made) greenhouse gas concentrations" via an enhanced greenhouse effect.
What is Greenhouse effect
Greenhouse gases effectively absorb thermal infrared radiation, emitted by the Earth’s surface, by the atmosphere itself due to the same gases, and by clouds. Atmospheric radiation is emitted to and by clouds. Atmospheric radiation is emitted to all sides, including downward to the Earth’s surface. Thus greenhouse gases trap heat within the surface-troposphere system. This is called the greenhouse effect
A thought to Pause…… Deforestation
We are witnessing an unprecedented and massive
collision between our civilization and the Earth.
And most of it is increase in cities This population rise puts pressure on vulnerable This population rise puts pressure on vulnerable
areas like forests for all our requirements (food, energy, etc)
The way we treat our forests is a political issue Much of forest destruction comes from burning.
(almost 30% of co2 released in atmosphere each year)
Important Note
During the 21st century, various During the 21st century, various computer models predict that Earth’s average temperature will rise between 1.8 and 4.0° Celsius (3.2° and 7.2° F).
A study by I PCC: What happens when world temperature rises by…. 1 DEGREE
* Shrinking glaciers threaten water for 50 million people * Modest increases in cereal yields in temperate regions * At least 300,000 people each year die from malaria, malnutrition and
- ther climate-related diseases
* Reduction in winter mortality in higher latitudes * Reduction in winter mortality in higher latitudes * 80 percent bleaching of coral reefs, e.g. Great Barrier Reef 2 DEGREES * 5-10 percent decline in crop yield in tropical Africa * 40-60 million more people exposed to malaria in Africa * Up to 10 million more people affected by coastal flooding * 15-40 percent of species face extinction (one estimate) * High risk of extinction of Arctic species, e.g. polar bear * Potential for Greenland ice sheet to start to melt irreversibly, committing world to 7 metre sea level rise
A study by I PCC: What happens when world temperature rises by….
3 DEGREES * In Southern Europe, serious droughts once every 10 years * 1-4 billion more people suffer water shortages * Some 150-550 additional millions at risk of hunger * 1-3 million more people die from malnutrition * Onset of Amazon forest collapse (some models only) * Rising risk of collapse of West Antarctic Ice Sheet * Rising risk of collapse of Atlantic Conveyor of warm water * Rising risk of abrupt changes to the monsoon
