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CLIMATE CHANGE: EVIDENCE AND FUTURE 5/22/17 CLIMATE CHANGE: EVIDENCE AND FUTURE Objective: I will explain the evidence collected by scientists to support climate change and predict future climate change. Page 83

Evidence for Climate Change Scientists have collected many pieces of evidence that support human influenced climate change

Evidence for Climate Change “In 2007 the Intergovernmental Panel on Climate Change concluded that “warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level.” Representing a consensus of hundreds of scientists, the report went on to note that human activity is “very likely” the cause.” Source: http://geology.skill.guide/earths-changing-climate-the-great-courses/

Greenhouse Gas Increase The Keeling Curve is a graph that plots the ongoing change in concentration of carbon dioxide in Earth’s atmosphere since the 1950’s. It is the best known illustration of the impact of humanity on the planet.

Global Temperature Increase Average temperature has risen about 1.1oC (2.0oF) in the past 200 years Directly correlated with an increase in CO2 concentrations Temperature increase cannot be attributed to natural sun cycles 2016 was the warmest year on record!

Arctic Sea Ice Loss The more ice that melts, the less reflective Earth’s surface is More absorption by water, therefore even higher ocean temperatures

Sea Level Rise 3.2 mm per year in the last 20 years or roughly 8 inches in the last century Mostly caused by the expansion of warmer ocean water Also caused by melting glaciers and ice sheets

Ocean Acidification Increased levels of CO2 in the oceans have made the oceans more acidic Threatening to all marine species that have shells

Looking into the Future If emissions continue as they do, an additional 2.6-4.8oC of warming is predicted by models by the end of the 21st century Sea levels will rise nearly 1 m by the end of the 21st century Ocean acidification will increase by 170% this century All can have an impact on human populations and the natural world