Across
- 2. frozen water that floats on oceans surface
- 3. gasses relased by human activity
- 6. how was atmosphere measured in the past
- 7. water expanding in volume as it warms
- 8. layer absorbs UV radiation
- 9. what time period was mostly carbon dioxide
- 10. permanent layers of ice on land
- 13. the sun emits more radiation when_____ sunsports are present
- 14. when was everything just Ice
- 17. adjust our lives to expected future climate
- 18. isotope of carbon used by plants in photosynthesis
- 19. carbon dioxide levels are highest in what season
- 20. vapor Variable gas
Down
- 1. Permanent gas
- 4. trapping of heat energy generated by the sun
- 5. how many separate layers on in the atmosphere
- 11. number of sunspots fluctuates about every____ years
- 12. carbon dioxide levels are lowest in what season
- 15. glaciers growing and advancing
- 16. absorbs carbon dioxide from the atmosphere