![]() ![]() The globe as a whole is now warmer than it’s been at almost any point since the end of the last ice age. The lake’s calcite layers became thicker during warm years pollen grains show how the forest composition shifted to include more heat-loving tree species.Īverage temperatures in southern Canada have increased about 1.5 degrees Celsius (2.7 degrees Fahrenheit) in this time. The amount of elm pollen plummeted - a consequence of the invasive fungus that was decimating North America’s tree populations at the time.Īll the while, greenhouse gas pollution made the planet inexorably hotter. Certain microbe species were eliminated locally. Still more sediments recorded irreversible losses. Acid rain, caused by pollution reacting with water in the atmosphere, diminished the calcite layers. The amount of fly ash increased eightfold in less than five years. ![]() A lighter form of nitrogen - a molecular signature of burning fossil fuels - proliferated. Other shifts weren’t necessarily new, but they appeared at scales ten or a hundred times greater than anything the lake had seen before. The element rarely occurs naturally on this planet it could only have come from nuclear weapon tests happening thousands of miles away. The sharpest sign of change was a surge in radioactive plutonium that started in Crawford Lake’s mud around 1950. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |