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Climate change: How do we know? National Aeronautics and Space Administration (NASA) http://climate.nasa.gov/evidence/ This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Source: NOAA) The Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives. The current warming trend is of particular significance because most of it is very likely human-induced and proceeding at a rate that is unprecedented in the past 1,300 years.1 Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. Studying these climate data collected over many years reveal the signals of a changing climate. "Scientific evidence for warming of the climate system is unequivocal." - Intergovernmental Panel on Climate Change Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities, and most of the leading scientific organizations worldwide have issued public statements endorsing this position. Please answer the following questions in regards to the 9 main SCIENTIFIC strands of EVIDENCE that global climate change is occurring? Sea level rise How much has the sea level risen in the past century? What TWO factors are the primary causes for sea level rise? What is the latest measurement of sea level rise? What is the current rate per year of sea level rise? Global temperature rise Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years. What is the warmest year on record? What does a 0.87 °C anomaly mean exactly? How many years has it been since the recording of a year of cooler than average temperatures? Warming oceans Where does all that extra heat go? How much has the top 700 meters of ocean warmed? Shrinking ice sheets What is basal melt? What is responsible for most of the continent's ice shelf mass loss? How much ice has Antarctica lost per year since 2002? How much ice has Greenland lost per year since 2002? Declining Arctic sea ice What is the rate of decline for September sea ice? Glacial retreat Why are glaciers ‘sentinels’ of climate change? Screen shot two glacier comparisons from the Global Ice Viewer Glaciers are sentinels of climate change. Extreme events Global warming is increasing the temperature of our lower atmosphere. How will this affect the amount of moisture in the air? The sun is the driving force behind the water cycle. Roughly how much of the sun's energy is absorbed by the Earth's land surface and water? http://pmm.nasa.gov/extreme-weather look at this link and list and describe 2-3 recent extreme weather events Ocean acidification How much has the acidity of ocean surface waters increased since the Industrial revolution? How many tons /year of CO2 has the upper layer of the ocean absorbed? Describe what causes coral bleaching How much of the CO2 produced by humans since 1800 has the oceans absorb? How much of the CO2 produced by burning fossil fuels since 1800 has the oceans absorbed? Decreased snow cover Describe snow covers role in regulating climate What are the consequences of too little snow and too much snow?