Global Warming and Climate Change SVN3E

Truth The globe is warming.

Consequences So what are the possible consequences (to the climate and the Earth’s ecosystems) of global warming?

Extreme Weather: Heat Waves A heat wave is a prolonged period of excessively hot weather, which may result in crop failures and deaths from hyperthermia (heat stroke). The 2003 European heat wave killed an estimated 35,000 people.

Extreme Weather: Drought Areas near deserts (e.g. much of Australia) are particularly vulnerable to drought.

Extreme Weather: Wildfires Heat waves and drought conditions also contribute to wildfires wildfires in Kelowna, British Columbia forced the evacuation of 17,000 people.

Positive Feedback Loops This can accelerate global warming in a positive feedback loop: wildfires add greenhouse gases to the atmosphere and remove CO 2 -absorbing trees.

Positive Feedback Loops The thawing of permafrost, releasing methane, is another example of a positive feedback loop.

Extreme Weather: Storms Global warming can also lead to increased evaporation and more intense storms. Hurricane Katrina strikes New Orleans, Aug 2005

Extreme Weather: Flooding These storms can result in flooding, particularly in areas that have developed wetlands. July 2010 flash flooding in Montreal

Loss of Glacial Runoff Melting of glaciers has been a problem for many people around the world who depend on runoff for their water supply (and hydroelectric power). Mount Kilimanjaro ice cover

Loss of Glacial Runoff Melting of glaciers has been a problem for many people around the world who depend on runoff for their water supply (and hydroelectric power). Mount Kilimanjaro ice cover

Loss of Glacial Runoff This is a particular problem in the Himalayas, since 40% of the world’s population is dependent on the rivers that drain the Himalayas.

Global Sea Level Rise Some areas like Bangladesh, however, are at greater risk from rising sea levels, which are caused by melting of the ice caps, e.g. over Greenland.

Global Sea Level Rise

Slow Ocean Currents Melting freshwater also affects ocean currents; it is predicted that ocean currents (including the Gulf Stream that warms the East Coast) will slow down or even stop.

Ocean Warming Ocean warming is a problem not only because it produces more intense hurricanes and because the expanded water causes further rises in sea levels but also because warmer water absorbs less CO 2 – another positive feedback loop.

Ocean Warming Warmer water is also not ideal for photosynthesizing algae – the producers of aquatic food webs.

Threatened Species About 40-70% of all species are at risk of extinction if the global temperature increases by only 3.3 o C.

Not-So-Threatened Species Though some species seem to be increasing their populations and expanding their ranges, such as jellyfish and malaria-carrying mosquitoes.