Anthropogenic Global Warming is a Threat

Climate reacts to whatever forces it to change at the time. We must ask why climate has changed in the past. There are many ways the Earth's climate can be affected. Something such as the sun getting brighter causing the planet to receive more energy and warms. When there are more greenhouse gases in the atmosphere the planet warms. It's true in the past climate change was caused by natural forces, but this doesn't mean we cannot cause climate change. It's like saying humans can't start brushfires because they happen naturally. In this day we are adding greenhouse gases to the atmosphere at an increasingly rapid rate. During the Cretaceous period submarine volcanic CO2 emissions were released into the atmosphere at rates high enough to cause atmospheric CO2 concentrations in excess of 1,000 ppm. This CO2 buildup also resulted from rapid sea-floor spreading related to the breakup and drifting apart of the Earth’s continents[1]There has been evidence that suggests that the Medieval Warm Period was warmer than today in some parts of the globe like the North Atlantic. However, evidence also suggest that in some places were much cooler than today, such as the tropical pacific. When the warm places were averaged out with the cool places, it is clear that the overall warmth was probably similar to the early mid 20th century warming. Since that early century warming, temperatures have risen well-beyond those achieved during the Medieval Warm Period across most of the Globe. This has been confirmed by the National Academy of Sciences Report on Climate Reconstructions[2]. Further evidence suggests that even in the Northern Hemisphere where the Medieval Warm Period was the most visible, temperatures are now beyond those experienced during Medieval times.[3] Here is the temperature pattern of the MWP vs today. The carbon plants collect from the CO2 in the air forms their tissues - roots, stems, leaves, and fruit. These tissues form the base of the food chain, as they are eaten by animals, which are eaten by other animals, and so on. As humans, we are part of this food chain. All the carbon in our body comes either directly or indirectly from plants, which took it out of the air only recently. Therefore, when we breathe out, all the carbon dioxide we exhale has already been accounted for. We are simply returning to the air the same carbon that was there to begin with. Remember, it's a carbon cycle, not a straight line.C02 does help plants, yet an abundance of it is harmful. Here is only 2 examples out of many.1.Too high a concentration of CO2 causes a reduction of photosynthesis[4] in certain of plants. There is also evidence from the past of major damage[5] to a wide variety of plants species from a sudden rise in CO2. Higher concentrations of CO2 also reduce the nutritional quality of some staples, such as wheat[6]. 2. As is confirmed by long-term experiments[7], plants with exorbitant supplies of CO2 run up against limited availability of other nutrients. These long term projects show that while some plants exhibit a brief and promising burst of growth upon initial exposure to C02, effects such as the "nitrogen plateau" soon truncate this benefit Please see the video on the right for more information http://www.youtube.com...There is evidence that shows humans are the cause of global warming Here is the first 5 of "10 Indicators of a Human Fingerprint on Climate Change"[8] 1.Humans are currently emitting around 30 billion tonnes of CO2 into the atmosphere every year[9]. Of course, it could be coincidence that CO2 levels are rising so sharply at the same time so let's look at more evidence that we're responsible for the rise in CO2 levels. 2.When we measure the type of carbon accumulating in the atmosphere, we observe more of the type of carbon that comes from fossil fuels [10]. 3.This is corroborated by measurements of oxygen in the atmosphere. Oxygen levels are falling in line with the amount of carbon dioxide rising, just as you'd expect from fossil fuel burning which takes oxygen out of the air to create carbon dioxide [11]. 4.Further independent evidence that humans are raising CO2 levels comes from measurements of carbon found in coral records going back several centuries. These find a recent sharp rise in the type of carbon that comes from fossil fuels [12]. 5.So we know humans are raising CO2 levels. What's the effect? Satellites measure less heat escaping out to space, at the particular wavelengths that CO2 absorbs heat, thus finding "direct experimental evidence for a significant increase in the Earth's greenhouse effect". [13][14][15]This shows that temperature is cyclic.A natural cycle requires a forcing, and no known forcing exists that fits the fingerprints of observed warming - except anthropogenic greenhouse gases. The Resolution is affirmed. Sources[1] Caldeira, K., and Rampino, M.R., 1991, The mid-Cretaceous superplume, carbon dioxide, and global warming: Geophysical Research Letters, v. 18, no. 6, p. 987-990.[2]http://books.nap.edu...[3]http://www.ncdc.noaa.gov...[4]http://resources.metapress.com...[5]http://www.pnas.org...[6]http://www.sciencemag.org...[7]http://www.nature.com...[8]http://www.skepticalscience.com...[9]http://cdiac.ornl.gov...[10]http://www.esrl.noaa.gov...[11]Ibid[12]http://www.sciencemag.org...[13]http://www.nature.com...[14]http://spiedl.aip.org...[15]http://www.eumetsat.eu...