Just last week, my thermodynamics professor talked at length about the facts of global climate change. Let me see what I can recall, so I can try to cut through some of the politics and bull that always surrounds this topic:
-Yes, the global climate has experienced change over the last several decades. If you check out the data, you can actually start to trace this to around 1850, which coincides with the start of the Industrial Revolution. (It may seem like a direct correlation, and I'll agree that it seems likely, but if you're calling yourself a scientist, you'd better have the whole picture before you start calling things "facts.") The phenomenon's not anything new.
-What I found interesting is that it is true that humankind's output of carbon dioxide represents a small fraction of the total global carbon dioxide cycle. The largest proponent of the cycle is the emission/re-absorption of CO2 from the world's oceans, followed by the cycle between photosynthesis and organism respiration. Also interesting is the fact that both the oceanic and plant cycles collectively lead to a negative flow of CO2 from the atmosphere. While humanity's input is small, it does put the net input of CO2 into the positive direction. We don't know yet whether this output will level out at some point in the future or is in a "runaway" effect. Another possible implication is that, were human activity to be curtailed somewhat, the planet would be able to remain at its current atmospheric levels without any problems.
-Yes, it's true that sea levels have risen. However, the media often grossly exaggerates this problem. Even the worst-case scenarios put the increase at about a meter over the next 50 years, which is a seemingly manageable value.
-While the increased frequency of hurricanes this year would make most people immediately think of a correlation, we just don't have enough data yet for it to be proven. We're only talking about an increased pattern over several years; that's far from enough time to be talking about long-term patterns.
-Yes, the Arctic ice is shrinking (as my professor put it, this poses problems for the polar bears, at least
). However, the Antarctic ice hasn't exhibited any significant reductions. Take that as you will.
-Currently, global warming is seen as a purely negative effect. However, there are areas in which it could actually prove to be beneficial. Treating it at the same level as an asteroid strike is pure media sensationalism. (My professor's reaction to a picture he showed in which a glacier had receded to leave a lake is that "it's much nicer-looking now than it was."
)
-Even if humanity stopped absolutely all CO2 output tomorrow, temperatures would continue to rise due to the levels that are already in the atmosphere. There's no "magic switch" that we can simply switch off, no matter what some people may say.
-One interesting thing to consider would be the use of biomass fuels such as ethanol. By growing plants for conversion into fuel and then its subsequent combustion, you could potentially have a self-sustaining cycle with no net release of CO2. Something to think about.
-Most importantly of all the points I've made, I want to reinforce that far too many people are calling for changes to be made without explaining exactly how they are going to be made. Let me put it bluntly: it is economically
impossible (not infeasible, impossible) to eliminate fossil fuels as a source of energy. Go ahead, try doing it; then watch the global economy collapse to hell. I don't have any easy answers as to what should be done; in fact, there aren't any. However, blaming policies of the past few years is just a waste of air.
To tell you the truth, I generally hate fearmongering headlines like the title of this thread. It doesn't do anybody every good to yell, "We're all gonna die!" It's not going to solve anything. Rather than wasting their breath, perhaps the scientists mentioned in the article should start working on some practical steps that should be taken to start to deal with the issue, and even above that, to determine beyond a shadow of a doubt exactly what impact human activity is having on global climate change. That's what we truly need, not Greenpeace propaganda.
