To The Daily Sun,
I don't personally know whether global warming is caused by human activity. Nor do I know how chemotherapy or lasers work. To develop an opinion on these things, I choose to rely on science, not motivated reasoning driven by political agendas.
A 2013 analysis of the peer reviewed studies by climate scientists on the causes of global warming found that over 97 percent of the papers that took a position concluded that humans are causing global warming.
In August of 2012 the American Meterological Society took the position that, "Warming of the climate system now is unequivocal, according to many different kinds of evidence." The statement provided a sampling of the evidence and then addressed human contributions as follows: "many of the observed changes ... are beyond what can be explained by the natural variability of the climate. It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases..." You can find the statement at "http://www.ametsoc.org/policy/2012climatechange.html
Lord Christopher Monckton is a well known "climate skeptic". He has been called a buffoon because of the variety of absurd claims he's made. One of them is that he can cure HIV. He has no formal training in science. His pronouncements on climate have been debunked by a wide range of scientists, often including the very sources he is allegedly quoting.
The Heartland Institute is another climate change denier. But it's a political organization not a scientific one. A Texas judge found that its president and CEO, Joseph Bast, lacked credibility. According to the judge, "while Mr. Bast described himself as an economist, he holds neither undergraduate nor graduate degrees in economics, and the highest level of education he completed was high school."
You can find information about climate change based on science by reading information from NASA, NOAA, and the EPA. If you want non-governmental sources, try the Center for Climate and Energy Solutions or the Union of Concerned Scientists. You can also read about climate change science in the journals Nature and Science.
Many climate change deniers, like Heartland, are funded by fossil fuel and other energy interests. I prefer independent experts who are actual scientists. If 97 percnet of structural engineers who studied it said that a bridge was likely to collapse if you drove over it, would you try to cross it with your family in the car? The risk is too high, for me. I would pay the price and go around. My belief is that we should have the same attitude when it comes to protecting our planet for future generations.