That Humans Are Causing Climate Change

Main point - Every major science academy in the west supports it, 97%-98% of scientist support it. 1. 75% of the 20th century increase in the atmospheric greenhouse gas CO2 is directly caused by human actions like burning fossil fuels. CO2 levels were 389ppm (parts per million) as of Apr. 2010 - the highest they have been in the past 650,000 years. This increase in CO2 was a substantial contributor to the 1"F to 1.4"F warming over the 20th century. 2. Human-produced CO2 is warming the earth, not natural CO2 released from the ocean and other "carbon sinks." CO2 from fossil fuel combustion has a specific isotopic ratio that is different from CO2 released by natural "carbon sinks." 20th century measurements of CO2 isotope ratios in the atmosphere confirm that the rise results from human activities, not natural processes. 3. Human produced greenhouse gases will continue to accumulate in the atmosphere causing climate change because the earth's forests, oceans, and other "carbon sinks" cannot adequately absorb them all. As of 2009, these carbon sinks were only absorbing about 50% of human-produced CO2. The other 50% is accumulating in the atmosphere. 4. Human greenhouse gas emissions, not changes in the sun's radiation, are causing global climate change. Measurements in the upper atmosphere from 1979 - 2009, show the sun's energy has gone up and down in cycles, with no net increase. While warming is occurring in the troposphere (lower atmosphere), the stratosphere (upper atmosphere) is cooling. If the sun was driving the temperature change there would be warming in the stratosphere also, not cooling. 5. Computer models show that increased levels of human produced greenhouse gases will cause global warming and other climate changes. Although these climate models are uncertain about how much future warming will occur and how it will affect the climate, they all agree that, to some degree, these changes will happen. The reality of climate change is not contradicted by this uncertainty. 6. Although the amount of human-produced greenhouse gases may seem small to some people, their warming potential is amplified by the water vapor positive feedback loop , allowing them to cause significant warming and climate change. As greenhouse gases heat the planet, increased humidity (water vapor in the atmosphere) results. Since water vapor is itself a greenhouse gas, it can double the warming effect of greenhouse gases such as CO2. 7. Human greenhouse gas emissions are heating the planet, and climate models consistently show that this warming causes an increase in the frequency and intensity of tropical cyclones. The fact that 1975-1989 had 171 category 4 and 5 hurricanes while 1990-2004 had 269 [51] of them (a 57% increase) validates these climate models and the reality of human-induced climate change. 8. Human-produced CO2 is changing the climate of the world's oceans. As excess CO2 is absorbed, oceanic acidity levels increase. Oceans have absorbed 48% of the total CO2 released by human activities and acidity levels are 25-30% higher than prior to human fossil fuel use. 9. An 8" rise in the ocean level has occured (1961-2003) due to human-induced global warming. Global sea levels rose an average of 1.8 mm (.07 in) per year between 1961 and 2003 and at an average rate of about 3.1 mm (.1 in) per year from 1993 to 2003. [3] This sea level rise is the result of warming waters and the melting of glaciers, ice caps, and polar ice sheets. From 1870-2004, a "significant acceleration" of sea-level rise occured, an important confirmation of climate change models. 10. Warming caused by human-produced greenhouse gases is changing the earth's hydrologic climate. Rainfall is increasing in many areas due to increased evaporation stemming from global warming. Higher temperatures are also causing some mountainous areas to receive rain rather than snow. According to researchers at the Scripps Institution of Oceanography, up to 60% of the changes in river flow, winter air temperature, and snow pack in the western US (1950-1999) were human-induced. 11. Warming caused by human-produced greenhouse gases is changing the rate of glacial melt and altering the local climate of many regions. Since 1850, records show a "strong increase" in the rate of glacial retreat. From 1961-2004 glaciers retreated about .5mm per year in sea level equivalent. According to the World Glacier Monitoring Service, since 1980, glaciers worldwide have lost nearly 40 feet (12 meters) in average thickness (measured in average mass balance in water equivalent). 12. Warming caused by human-produced greenhouse gases and soot (black carbon) produced from burning of fossil fuels and deforestation, is reducing the size of the Arctic ice cap. A smaller ice cap reflects less of the sun's energy away from the earth. This energy is absorbed instead, causing air and water temperatures to rise. From 1953"2006, Arctic sea ice declined 7.8% per decade. Between 1979 and 2006, the decline was 9.1% each decade. Climate models predict that Arctic sea ice will continue to retreat through the 21st century further disrupting the global climate. [15] 13. Many organizations believe that human activity is a substantial cause of global climate change. These groups include: the World Meteorological Organization (WMO), the Intergovernmental Panel on Climate Change (IPCC), the InterAcademy Council, the Network of African Science Academies, the European Science Foundation (ESF), the European Space Agency (ESA), the Royal Society (UK national academy of science), the US National Academies of Science, the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), and the US Environmental Protection Agency (EPA). 14. Nearly all climate change studies show humans as the main cause, and studies which contradict this claim are often funded by petroleum companies, making their conclusions suspect given the obvious conflict of interest. From 2004-2005, ExxonMobil gave $2.2 million in grants for climate change research to organizations that deny human caused climate change. In 2006 US Senators Olympia Snowe (R-ME), and Jay Rockefeller (D-WV) chastised ExxonMobil for providing more than $19 million in funding to over 29 "climate change denial front groups."