1. 9.1Evidence of Changing Climate

2. Rising Temperatures  Records of Earth’s average temperatures over the past 100 years  Records show avg. temperatures go up and down each year but an increase in temperature over the long-term trend.  In the last 55 years Canada increase 1°C (2.5 °C in the Yukon)

3. Melting Glaciers  Average size of glaciers have decrease as global temperatures have increase  Used for drinking water. Almost half the world depends on them for water.  Ice sheets in Greenland and Antarctica are melting  Artic sea ice is melting more in the summers. It reforms in the winter but more and more is melting in the summers.

4. Rising Sea Levels  Rising over the past 120 years  Rising twice as fast since 1993  Results in devastating floods  WHY?  Melting glaciers?  Thermal expansion: increase in volume as temperatures increase  Decrease in ground water in North America

5. Changes in Severe Weather  Severe weather events like heat waves and hurricanes have increased and become more intense

6. Changes In Precipitation Patterns  Northern hemisphere has increasing precipitation and more is falling as rain  Southern Africa, Mediterranean and Southern Asia are becoming drier.

7. Changing Seasons/Changes in Ecosystems  Cold days and frosty nights are coming later in the year and ending earlier in the spring  Plants flowering earlier in the spring/animals breeding earlier too.  Animal and plant communities are migrating towards the poles and higher altitudes  Undesirable insects and plants are moving north into new regions

8. 9.4 Greenhouse Gases Changing Climate  Scientists study both natural and human sources of greenhouse gases.  Studies show that about half of human-produced CO2 ends up in the atmosphere (not absorbed by plants and oceans)

9. Anthropogenic Greenhouse Gases:  human produced green house gases  carbon dioxide: fossil fuels and deforestation  Methane: farming, decaying of organic materials, coal mining etc.  nitrous oxide: management of livestock feed and waste, nitrogen fertilizers  Chlorofluorocarbons: refrigeration agents  Anthropogenic Greenhouse Effect : green house effect caused by human activities

10. Homework:  pg 378 #’s 1-7  Pg 389 #’s 1, 4-6