The Earth's climate is actually evolving at a rather slow pace and has done so through the ages in addition to the extinction that occurred in connection with the asteroid that killed the dinosaurs.
So it is a slow change in the climate we are witnessing even now, but today's temperatures are surprising and rising even faster than before.
We have had a general temperature rise for a long time, and maybe it's not so strange because we get so much solar radiation here on earth. Solar radiation is necessary for life on earth, but solar radiation causes the planet to change constantly. The climate is thus mainly affected by the sun and therefore our own impact can be considered marginal if compared with the sun's forces.
Man consumes the earth's resources at a furious pace and this puts us at risk of not being able to live a sustainable life here on earth.
There is simply a risk that the earth's resources will run out.
In addition, with the earth's constant rise in temperature, it is guaranteed that our future climate will be extreme in terms of temperature. It will finally be a desert landscape on our former green continents if the temperature is only raised four degrees celcius (39 degrees fahrenheit) more!
Finally when we see our temperature rising we are also at risk due to the levels of sea level rise globally around the world. Our global ice sheets will melt after we hit a four degree raise and then our lands will be completly overflooded and any habitation will eventually be impossible, therefore we must find a way to live our future lives in space (preferably on the moon).
And it will happen, even if it does not happen in our personal time here on earth.
What do we do then - read more under Survival.