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released from burning fossil fuels has a different chemical signature than carbon dioxide released by living animals and plants [15]. Spectrometry shows the increase in temperature is from the burning of fossil fuels [15].
The primary gases in the atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons, as well as some other exotic, manmade compounds [15]. Overall though, greenhouse gases are good [15]. As radiation from the sun comes through the atmosphere and warms the earth, greenhouse gases trap outgoing longwave radiation and keep the planet 33 degrees centigrade warmer than it would otherwise be [15]. But as we have added more greenhouse gases - especially carbon dioxide - additional warmth is becoming a problem [15].
In recent decades we have developed sophisticated ways to measure the energy that comes into and out of the planet (not just ground based but also advanced satellites) [15]. Measures of energy in and out have been tracked by scientists over recent decades [14]. One study, conducted by John E. Harris, Helen E. Brindley, Pretty J. Sagoo, and Richard J. Bantges, compared satellite measurements over the outgoing longwave radiation [15]. Over almost three decades (1970-1997) - after correcting for increase temperatures in humidity - they found change in outgoing radiation due to greenhouse gases [15]. The wavelengths for greenhouse gases increased absorption and the study concluded, “[The] results provide direct experimental evidence for a significant increase in the Earth’s greenhouse effect that is consistent with concerns over radiative forcing of climate [15].”
If less energy is getting out, more must be coming back to warm the planet. Scientists have measured this as well [15]. In a study by Kaicun Wan and Shunlin Liang they collected data from 3,200 ground stations compiled over 25 years which showed increased downward longwave radiation [15].
Scientists have also looked at other potential causes of warming [15]. Measurements are available of solar irradiance which have been flat since the 1950s [15]. Effects from the ocean, like el nino, and the influence of volcanic eruptions have also stayed consistent [15]. More importantly than temperature readings or climate models though, are the ways the earth is showing us indications of climate change [15].
Shifts in the way ecological systems work - when spring arrives, when flowers bloom, when birds fledge, where species and plants live and when they do things in the year - are moving towards colder places and seasons as they respond to the warming [14]. In a famous study by NASA researchers, it was found that all over the planet physical systems and living things are showing a trend [15]. Altogether they looked at over 29,000 sets of physical and biological data (ie. seasons when birds migrate, blooming of flowers and plants, migration and mating of fish and animals, days when ice breaks on frozen rivers and lakes, the onset of winter and spring) [15]. Of these, 90% showed changes “...in the direction expected as a response to warming [15]..”
Birds and bees don’t have a political agenda - at least we think not [15]. And this is a headache for climate deniers who want people to believe it’s all some kind of giant conspiracy and the birds are in on it. However, the plots get thicker. The great lakes have lost most of their winter ice during the last three decades, and since temperatures are rising, the ocean is expanding and sea-levels are rising [15]. So, the water systems must be in on it too. Additionally, as more snow melts, the outflow in Northern regions has increased and Northern polar sea ice has been in steady decline over the last 3 decades [15]. The great ice sheets of Antarctica and Greenland are losing ice in more mass than anyone would’ve predicted [15]. And, glaciers all over the planet are melting and shrinking at increasing rates [15].
The change is also evident to farmers and gardeners as the growing season for plants has moved steadily northward in the last several decades [14]. And, with more moisture in the atmosphere due to warming, precipitation events are getting more extreme both in Northern and tropical areas [14].
The evidence is clear, overwhelming, from multiple lines of evidence, and consistent worldwide as demonstrated in 150 years of scientific research.