The Rate Debate Slowing
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Tipping Points SoonTipping points are approaching now - make warming irreversible - inaction multiplies certainty Risby 11 — (James Risby, Researcher, Marine and Atmospheric Research at CSIRO, PhD in Climatology from MIT, 6/15/11, "Speaking science to climate policy," The Conversation, http://theconversation.edu.au/speaking-science-to-climate-policy-1548) We’re only a few decades away from a major tipping point, plus or minus only about a decade. The rate at which the ice sheets would melt is fairly uncertain, but not the result that says we are very close to a tipping point committing to such melt and breakdown. If we were to keep remaining emissions inside the 250–450Gt carbon allocation, we would need to take account of the inertia in energy systems and infrastructure, which set some limits on the maximum rate that emissions can be reduced. To stay within the budget, we can’t hope to emit 10Gt a year (the present emissions rate) for the next thirty years and then reduce emissions suddenly to zero. Rather, net emissions would need to be phased down to zero to stay within the budget. The longer stringent emissions reductions are delayed, the more drastic they must be to stay within the 250–450Gt budget. With more than a small delay, the reductions needed are faster than can be achieved in turning over the stock of emitting infrastructure. Thus, if we were to stay within this budget, dramatic emission reductions would have to begin now. Delayed action on stringent emissions reductions almost certainly implies overshooting the thresholds and locking in vast long term impacts. Tipping points coming now - positive feedbacks make warming irreversible and fast Worth 9 (Jess Worth, editorial and feature writer for New Internationalist, April 2009, "Can Climate Change be Averted?: The first tipping point to climate disaster is already here," CCPA Monitor 15(10)) The time for words of warning is long gone. One need only tune in briefly to the panicked tones of the world's leading climate scientists to grasp that we are already in a crisis. The Arctic ice-sheets are melting far faster than the UN's Intergovernmental Panel on Climate Change projected only last year. Their conclusion that the world needs to reduce greenhouse gas emissions by 80% by 2050 - no mean feat in itself - was based on the assumption that Arctic summer ice may be gone by the end of the century. It is now predicted to be gone in the next five years. Arctic sea-ice acts as a refrigerator for the globe. Without it, global warming will happen even faster. It also contributes to the "albedo effect" whereby white surfaces reflect more solar radiation than dark ones. As ice and snow disappear, darker ocean and land absorb more heat from the sun and add to warming. This in turn affects the Arctic permafrost, which currently locks away twice as much carbon as is now in the entire global atmosphere. That permafrost is starting to thaw, about 80 years ahead of schedule. We have reached the first climate "tipping point." As temperatures rise, changes are triggered in the planet's systems which create "positive feedbacks," further contributing to global warming, and potentially unleashing rapid, uncontrollable, and irreversible climate change. It's still not too late to prevent a catastrophe. But only just. Global warming has already resulted in a temperature increase of nearly 1°C, and we are committed to further warming caused by greenhouse gases already emitted around 0.2°C per decade. But scientists say that, if warming is kept below 2°C, we have a good chance of avoiding the worst effects of climate change. Tipping Points ImpactEmpirically tipping points are real - Cook 9 (Kerry Cook, Geosciences @ UT Austin, 2009, "Abrupt climate change: atmospheric tipping points," IOP Conf. Ser.: Earth Environ. Sci., Vol. 6(6)) The atmosphere has a low heat capacity, and so it can change abruptly when forcing functions change rapidly. For example, rapid changes in ocean temperature or land surface conditions will cause a similarly rapid change in the atmosphere. But abrupt changes in climate can also come about through the atmosphere’s response to smooth changes in forcing when certain tipping points, or thresholds, are reached. Several types of atmospheric tipping mechanisms are discussed, with examples taken from seasonal variations of today’s climate and abrupt climate change on century and millennial time scales. Some tipping point mechanisms occur purely because of the nonlinearity of the atmosphere’s internal dynamics. One example is the rapid change in rainfall distributions that occur virtually every spring over northern Africa, known as the monsoon jump. Other examples relate to the vertical stability properties of the atmosphere, which are especially relevant for understanding drought and floods. Tipping points also arise due to phase changes of water within the atmosphere. For example, cooling to a threshold temperature will cause water to condense and form a cloud. As a result, sudden changes in atmospheric and surface heating rates will occur, and feedbacks from the condensational heating released into the atmosphere can drive a strong dynamical response with consequences for regional climate. Sudden aerosol loading, when threshold surface winds speeds are reached for suspending particles, also presents potential for abrupt change that may be felt on global space scales. We do not fully understand how effective these tipping points can be for changing climate, and we probably have not identified all of the potentially important tipping points. We need to investigate the mechanisms of these abrupt changes so they can be properly represented in climate models. Because of the existence of these tipping points, and their ability to cause rapid climate change, we need to prepare for surprise as climate changes. Directory: files files -> Answer True False 2 points Question 2 files -> Integer programming and game theory files -> 4 Integer Programming files -> Bpa vehicle Window Repair Scenario #1 task: Procure vehicle window relacement. 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