Earth's climate has changed radically over its 4.5 billion year history, back and forth between "greenhouse" periods (with little or no ice, even at the poles) to "icehouse" ones (with ice covering the entire planet, even at the equator). Several less severe events have taken place in the last 540 million years, and the cause was one or more of these: solar radiation, earth's distance from the sun, active volcanoes, and the effects of biological life before man (Link). Large meteor strikes, which produce enough atmospheric debris to block out the sun for long periods, have caused sudden ice ages. Especially the one 65 million years ago that killed off the dinosaurs and ushered in the age of mammals; including us human beings (Link).
Two thousand years ago the Romans grew grapes in northern England, which is inconceivable today. Tree ring studies confirm that the world was warmer then than now (Link). The climate cooled in following centuries for some unknown reason, but warmed again between 900 and 1300 A.D., a time known as the Medieval Warming Period. Earth's population was small and there was almost no industry and production of greenhouse gases like methane and carbon dioxide. But the glaciers retreated, food production and population boomed, and the Vikings settled in Greenland.
Then, inexplicably, the climate relapsed into the Little Ice Age, which lasted from the early 1300's to the mid-1800's. The Vikings were frozen out of Greenland, and the Thames River in England sometimes froze solid in winter. Once again the planet began warming, but even our present day, seemingly-warm climate is classified as an "icehouse" period, because the polar ice sheets are present and they advance and retreat seasonally (Link).
Earth's population a thousand years ago was about 300 million, and it had changed little since the Golden Age of Greece. It reached a billion in 1810. Clearly, the earth's climate changes up to that time were independent of human activity. Today there are 7.4 billion people on earth, and we have enormous industry that may indeed influence our climate. But note that we're still in an "icehouse" climate regime of polar ice sheets [see above].
If a global treaty limiting greenhouse gases could be reached and enforced, it would make sense to sign on. Smoke and other pollutants are harmful to everyone. But the only nations who really care to do this are the EU, the U.S., Australia, and Canada. The rest of the world, over six-billion people, refuses to sign such a treaty because it's costly, and would stifle their industries to a degree.
The global media persists in maintaining the fiction that scientists all agree we must change our western economies to "set an example", and reverse the climate direction of earth. However, this panel of Australian climate scientists is typical of a large number of atmospheric experts who disagree:
It's a fact that global economic forces, often connected with governments, are behind the man-made global climate change story. It's extremely profitable for political-economic groups to create a demand for products that only they can provide. This is the very definition of a monopoly. Trillions of dollars and the power to seriously damage competing national economies are a powerful motive. At the moment, the monopolists are winning. Scientists are fallible people, not saints, and opinions can be purchased from the global media with the right amount of money. The stakes are huge, and well worth the massive investment required.
We who have faith in God recognize that the power to change earth's climate rests with God, and not with man, yet. The time may come when we will acquie that power, but we don't have it now.