I don't think anyone would argue that all of today's climate is the fault of man-made emissions. However overwhelming evidence indicates that man-made emissions (and other factors such as conversion of forests to grazing land) are contributing to an increase in oceanic acidity, and an overall increase in global temperature. I don't think it's fair to call people that communicate this evidence, or action based on it as 'global alarmists'.

I am a scientist by profession. I study cancer biology, but I have read many scientific publications on global climate change, usually in interdisciplinary journals such as Nature or Science. I'm interested in the science behind it, partially because I am interested in past global climates. I live in Michigan, which at one point used to be a warm sea, and at another was covered in glaciers. Global climate change fascinates me. (Did you know that Lake Superior is only 10,000 years old, but some of the rocks around it are 3.5 Billion years old!? It's like a rain puddle!) But, I don't care if global warming right now is real or not. I really don't. It simply is or it isn't.

However, if you look at the evidence, you can see that we have increased the amount of carbon in the atmosphere while at the same time reducing some large carbon sinks. Carbon helps capture sunlight as heat. You can show that in a simple lab setup. We have abundant evidence from (many many independent sources now) that average global temperature is on the rise. What is more, a warmer atmosphere holds more water, which traps much more heat than CO2. Also, permafrost melt is increasing, and releasing an increasing amount of methane into the atmosphere, which is an even more potent greenhouse gas. Finally, massive deforestation has diminished a large carbon sink, and the ocean's CO2 level has been rising, which decreased its effectiveness as a CO2 sink. The data demonstrates an interesting picture. The earth's atmosphere is in a warming cycle, and CO2 emissions contribute to it.

I think that people often think of the atmosphere as vast. However, if you were to shrink the globe down to a bowling ball, Mt. Everest would have a height similar to a ridge of your fingerprint. Now, consider that at the top of Everest, you are getting outside of the breathable atmosphere. The atmosphere around the earth is a very thin film, one that has been demonstrably affected by life many times over in its history. (consider the Great Oxygenation Event http://en.wikipedia.org/wiki/Great_Oxygenation_Event) In fact the balance of CO2 and oxygen we have right now is a direct consequence of life on earth.

Anyway, it really doesn't matter one way or the other if you can find someone that disagrees with anthromorpholgic climate change. What only really matters is the data collected, and how that data can be best interpreted based on known phsyical properties. That is, if there is a contradiction between the data, your theory, and established physics, then something is wrong. Where we stand, we have an abundance of data that suggests that the least contradictory theory that can be constructed is: that we have increased the atmosphere's ability to capture heat from sunlight due to the gases our industry releases, and the removal of some atmospheric sinks for those gases. And in addition, there is evidence a positive feedback loop (such as permafrost melt, and methane release from a warmer ocean floor) that suggests the climate temperature rise could continue for some time. That's why the scientific community at large is onboard with taking action to reduce our contribution. I think it's important to note that today's global temperature is cooler than its historic mean. There's really no reason why we can't increase it.

Personally, I think it's sad that this issue has become a politicized debate in the US. It's very interesting stuff, and the consequences are something that we are able to see firsthand. I like to remember that Michigan is going to be covered in ice again someday. It's also probably going to be covered in ocean again too. The global climate doesn't have any long-term balance or natural state. It certainly doesn't owe us not to change. If we change the atmosphere, the climate changes too. It's just cause and effect.

btw, NASA has a pretty good overview of evidence that has been gathered, and changes that are occurring around the world due to the increase in temperature: http://climate.nasa.gov/evidence/

I really urge you to check it out. Forget the debate about what we should or shouldn't do about it. (Personally, I don't think we can do much) It's just damn interesting in its own right.