Climate Change

4. are darker areas on the sun’s surface created by intense magnetic fields.
6. has a much thinner atmosphere, with no greenhouse effect.
10. on Earth ended about 10-20 thousand years ago.
11. lasted between about 950-1250 C.E., with warmth in some regions exceeding the current post-industrial era.
13. weakened the greenhouse effect due to the removal of carbon dioxide and oxidation of methane.
16. are any permanent layers of ice covering a tract of land, especially in the polar regions.
17. evolved the ability to perform photosynthesis, absorbing carbon dioxide and releasing oxygen.
19. contains the air we breathe and every aspect of what we call weather.
20. very dry and less dense layer above the troposphere.

1. drilled into the glaciers in
2. ike land ice, are shrinking worldwide.
3. was a period of cooling that lasted from the 16th-19th centuries.
5. the area between the stratosphere and upper troposphere, due to the similar temperatures.
7. Period from 4.6 billion to 540 million years ago, the Earth’s atmosphere was mostly carbon dioxide and nitrogen.
8. is frozen seawater that floats on the ocean’s surface.
9. population is expected to decline by two-thirds by 2050, reaching numbers less than 10,000.
12. being able to cross ice-free seas and colonize southern Greenland and Newfoundland.
14. Earth’s overall surface temperature is lowered enough that glaciers form at the poles and in mountainous areas.
15. the thin layer of gases that surrounds the earth.
18. and Greenland.