Global Warming What is it? Why is it happening? Evidence that it is happening. What are the consequences? What can we do to stop it? NASA Video NASA Video

What is global warming? An increase of the average temperature of the earth An increase of the average temperature of the earth The earth’s average temperature has increased 0.6 o C or 1 0 F increase in temperature over the 20 th century The earth’s average temperature has increased 0.6 o C or 1 0 F increase in temperature over the 20 th century IPCC

Why is it happening? The natural greenhouse effect is being increased by extra greenhouse gases trapping more heat The natural greenhouse effect is being increased by extra greenhouse gases trapping more heat Greenhouse gases Greenhouse gases –Water Vapor –Carbon Dioxide –Methane –Smaller amounts of other gasses

Greenhouse gas: carbon dioxide 31% increase in carbon dioxide in recent years 31% increase in carbon dioxide in recent years –from fossil fuels combustion, open fires, also increases when you cut down trees that previously were absorbing this gas

What is the Greenhouse Effect? Greenhouse effect video

Sunlight comes in and some reflects off of clouds back into space

Sunlight comes in and some is reflected off of the surface of the earth

Sunlight comes in and is absorbed as heat at the surface. Some heat is then emitted from the earth and is released to space.

Some heat is emitted from the earth and is absorbed by greenhouse gases. Some gets reflected back to the earth.

Global Warming Global warming occurs when there are too many greenhouse gases in the atmosphere. Global warming occurs when there are too many greenhouse gases in the atmosphere. Greenhouse gases (like CO 2 and methane) trap heat escaping to space and warm the planet more than it should. Greenhouse gases (like CO 2 and methane) trap heat escaping to space and warm the planet more than it should.

Evidence Global Warming is happening The north and south pole are showing signs of warming before the rest of the earth The north and south pole are showing signs of warming before the rest of the earth Antarctic (south pole) peninsula ice shelves calving off Antarctic (south pole) peninsula ice shelves calving off 2.5 o C recent warming on the peninsula (50 year warming?) 2.5 o C recent warming on the peninsula (50 year warming?) Larsen B ice shelf 2002 (opening scene in “The Day After Tomorrow”) Larsen B ice shelf 2002 (opening scene in “The Day After Tomorrow”) Video: Canadian Arctic Video: Canadian Arctic Video: Canadian Arctic Video: Canadian Arctic

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17 Feb 2002

23 Feb 2002

05 March 2002

“Arctic temperatures have increased in recent decades. Compared to the past 50 years, average temperatures from January through August, 2005 were 2 to 3 degrees Celsius warmer than average across most of the Arctic Ocean.” -NSIDC “A record loss of sea ice in the Arctic this summer has convinced scientists that the Arctic has now entered an irreversible phase of warming which will accelerate the loss of the polar sea ice that has helped to keep the climate stable for thousands of years.” - NSIDC fall 2005

Ice Albedo Feedback Decrease amount of ice and snow Decrease albedo: More area to absorb sunlight rather than reflect it Increase Heat Therefore this is POSITIVE Feedback! It reinforces the initial heating. Cold Cold to hot Ice to no ice

Quelcaya Ice cap, Peru Qori Kalis glacier Qori Kalis glacier : retreat : retreat rate of 4 m/yr rate of 4 m/yr by 1995: retreat rate of 30 m/yr by 1995: retreat rate of 30 m/yr (slide compliments (slide compliments Adina Racoviteanu)

Kilimanjaro, East Africa (5895 m) Retreated by 87% from 1990s (Thompson et al., 2002)

The challenge is this… Carbon dioxide stays in the atmosphere for decades Carbon dioxide stays in the atmosphere for decades –Even if we stopped emitting it today, our extra carbon dioxide would continue to cause problems for almost a century to come!

Why do we care about global warming? Main reasons… Melting the ice caps will increase sea level enough to displace millions of people currently living on the coast Melting the ice caps will increase sea level enough to displace millions of people currently living on the coast Growing food may become increasingly difficult due to floods/droughts/salt water entering our fresh water supplies Growing food may become increasingly difficult due to floods/droughts/salt water entering our fresh water supplies

Effects of rising sea levels in North America and Europe

Global warming can cause an Ice age!!! Heat the earth Heat the earth Melt the ice caps Melt the ice caps Decrease the salinity at the poles Decrease the salinity at the poles No deep water is formed No deep water is formed The global thermohaline ocean circulation shuts down ( year cycle) The global thermohaline ocean circulation shuts down ( year cycle) The hot water stays at the equator and the cold water stays at the poles The hot water stays at the equator and the cold water stays at the poles Europe would be the first place to notice the most significant difference and have effects of an Ice Age. Europe would be the first place to notice the most significant difference and have effects of an Ice Age. BUT…water is heavy, it has a lot of momentum, so it will take a long time for the oceans to just stop moving! (in the movie it took about a week, in reality...at least 10 years) BUT…water is heavy, it has a lot of momentum, so it will take a long time for the oceans to just stop moving! (in the movie it took about a week, in reality...at least 10 years)

Another reason to care about global warming: tropical diseases could come to new climates like ours as we become warmer! According to the World Health Organization, each year nearly 500 million people become infected with malaria, and nearly three million — mostly children — die from it. Areas around the world facing the greatest risk, shown in red, harbor some of the world's most impoverished people. According to the World Health Organization, each year nearly 500 million people become infected with malaria, and nearly three million — mostly children — die from it. Areas around the world facing the greatest risk, shown in red, harbor some of the world's most impoverished people.

Local Effects of Climate Change CANADA Polar ice caps melting Polar ice caps melting Soil drying up Soil drying up Farmland changing Farmland changing Temperature increases (highest in the poles) Temperature increases (highest in the poles) SOUTHERN ONTARIO smog is expected to intensify. smog is expected to intensify. Water levels will drop Water levels will drop soil moisture in the region will decrease soil moisture in the region will decrease

In other parts of the world, the effects of global warming will be much more deadly. In other parts of the world, the effects of global warming will be much more deadly. Flooding in Bangladesh is expected to increase by up to 40 per cent this century as global temperatures rise. Flooding in Bangladesh is expected to increase by up to 40 per cent this century as global temperatures rise. The population of Bangladesh is greater than 150 million The population of Bangladesh is greater than 150 million

What can we do to stop it? Change to renewable energy sources that do not produce methane or carbon dioxide Change to renewable energy sources that do not produce methane or carbon dioxide Suck greenhouse gases out of the air Suck greenhouse gases out of the air –Trees –Algae –Machines

Deal signed in December, 2009 by most countries Deal signed in December, 2009 by most countries Agrees to making cuts, but is not binding. Agrees to making cuts, but is not binding. Recommendations only Recommendations only Still details to hammer out about specifics Still details to hammer out about specifics Copenhagen Climate Agreement

Or we could let it happen We will pay the price! We will pay the price! –Money –Food –Human lives –The comfort of our North American living will be gone Rick Mercer Video Rick Mercer Video Rick Mercer Video Rick Mercer Video