GLOBAL WARMING Abnormal increase in global temperature by excessive emission of gases such as CO 2, NO 2, CH 4, HFCs, PFCs, SF 6 because of human action The greenhouse effect is a natural atmospheric phenomenon that keeps the Earth's temperature, to retain some of the energy from the sun. The increased concentration of carbon dioxide CO 2 from the use of fossil fuels has led to the intensification of the phenomenon and consequent increase in global temperatures, melting polar ice and rising sea levels.
What is Global Warming? Global Warming is the increase of Earth's average surface temperature due to effect of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation, which trap heat that would otherwise escape from Earth. This is a type of greenhouse effect.
1. The sun sends out energy as heat and light. This energy comes to our earth during the day time. 2. Some of the sun’s rays get ‘trapped’ in the atmosphere. 3. Some of them get reflected back into space. 4. The ones which get through the atmosphere warm the earth up.
All the time, the earth radiates heat into space, which cools it down. We only really notice this at night, when there is no heating from the sun. Some of the heat going out is trapped by the atmosphere. This is what makes our planet warm enough to live on. But if too much heat is trapped, our planet will warm up and the climate will change.
What is the atmosphere and why does it trap heat? The atmosphere is the air around the surface of the earth. It is made from a mixture of gases. We need it for animals and plants to survive. Some of the gases act like a blanket, trapping heat. These gases are called ‘greenhouse gases’. This is known as the ‘Natural Greenhouse Effect’. Without it, the earth would be much colder. (the atmosphere is really much thinner than it looks above)
So why is global warming happening? (the atmosphere is really much thinner than it looks above) Some things that people do are increasing the amounts of the greenhouse gases in the atmosphere, so more heat is trapped. The heating of the earth through human activities is called the ‘Enhanced Greenhouse Effect’ and this is causing the earth to heat up, or global warming. Global warming doesn’t just mean that the earth gets hotter, it means that the whole climate is changing.
Natural Greenhouse effect More heat is trapped and causes global warming Atmosphere traps some heat Some heat goes out to space Quite a lot of heat is trapped and the earth is warm enough for life. Enhanced Greenhouse effect Heat radiates from the earth Atmosphere has more greenhouse gases Atmosphere traps more heat Less heat goes out to space
Which gases in the atmosphere trap heat? The atmosphere is made of 78% Nitrogen and 21% Oxygen. But these gases don’t trap heat and cause global warming or climate change. What % of the atmosphere is left? The gases which trap heat make up less than 1% of the atmosphere! They are called the ‘greenhouse gases’. The main greenhouse gases are: Carbon dioxide Methane Nitrous oxide Ozone Water vapour Halocarbons Human activity increases the amount of these gases in the atmosphere
How do humans increase carbon dioxide levels in the atmosphere? Burning fossil fuels releases the carbon dioxide stored millions of years ago. Most of the increased carbon dioxide comes from fossil fuels Deforestation releases the carbon stored in trees. Less trees also means less carbon dioxide can be removed from the atmosphere.
How do humans increase methane levels in the atmosphere? The amount of methane in the atmosphere has increased by two and a half times since the Industrial Revolution. Increased rubbish in landfill Increased livestock farming Increased rice growing Methane is also released when fossil fuels are extracted Methane is produced when bacteria rot organic matter
GLOBAL WARMING GLOBAL WARMING The ozone layer: Earth Shield. Filter ultraviolet rays from reaching the surface of our planet & protect to us against those UV Rays that are very harmful to life due to its high mutagenicity altering the DNA of living organisms, causing cancerous tumors among other effects.
CALENTAMIENTO GLOBAL Efecto invernadero: ¿fenómeno positivo y/o negativo?
GLOBAL WARMING GLOBAL WARMING Sunbeams surpluses should "get out" of the atmosphere because it has formed a "layer" of harmful gases that prevent it seeping so increase in global temperature
GLOBAL WARMING Effect of Temperature Increasing the temperature will be between 1.4 ° C to 5.80 ° C, accompanied by growth of 80 cm. in sea level produced by the melting of the polar caps. (calculated to be in a period of 50 years. Stern, N.)
CONSEQUENCES OF GLOBAL WARMING : Some effects of the global Warming: 1. Rising in sea level 2. Changes in the ecosystems. 3. Alteration in the production cycle of food
4. Modification of the hydrological cycle 5. Extinction of animal and plant species 6. Increasing of the temperature and the concentration of CO 2. CONSEQUENCES OF GLOBAL WARMING :
CALENTAMIENTO GLOBAL 7. Melting glaciers. 8. Increase of the flooding. 9. Modification of the ecological niches 10. Reduction of drinking water
CALENTAMIENTO GLOBAL 11. Reduction of Grasslands 12. Extreme climate changes droughts(sequías) and torrential rain) 13. Rising temperatures in the towns.
Emissions of CO 2 in USA (Combustion) by Sector y Kind of Fuel
Fossil ice melts! Antarctica contains 30 million cubic kilometers of ice. Currently estimated melt ice 36 millas³ annually.. Greenland lost 100 billion metric tons of ice annually between 2003 and 2005.. If ALL the Greenland ice melts, the sea level would rise 7.2 meters..
Land-locked Ice Melts Into The Sea 90% of the fresh water on Earth is in ice. If ALL it melts, sea level would rise 61.1 meters.