I was sad when I heard that we were giving up on this earth and trying to terraform mars. The melting of the polar ice caps has begun and there is nothing we can do about it. We can stop putting greenhouse gasses into the atmosphere but that wont do anything about the gasses that are already there. The sea level is going to keep rising over the course of the following years and the temperature is going to continue to climb which is going to cause mass extinction. On an unrelated note, Yellowstone is showing signs of nearing an eruption which will shoot debris into the atmosphere, blocking the sun and possibly throwing us into another ice age. So take your pick on how you think the world will end and hopefully we will have colonized mars by then.
Our environment's health, such as it is, is in the decline. Since the year 1990, we have been past the point of no return, and rather than finding a solution to the problem since then to lessen the burden of climate change on future generations, we have elected to continue to pollute our atmosphere. We behave as though we have an infinite amount of resources available when, in reality, our resources are finite. We behave as if our environment can repair itself, when in reality it won't. Twenty years ago, our environment may have been able to recover on its own, assuming we quit polluting it with fossil fuel emissions completely, but today, we are bolted to this roller coaster climate change nightmare, with our brake lines cut.
To say it is "to far gone" is simply mistaken, and you state that "... I heard that we were giving up on this earth and trying to terraform mars." yet I see no citation for this evidence. While I do agree that it is to late to save the vast majority of the ice caps, it is not impossible to stop or at least slow down the melting to an acceptible level. Regarding your cries of mass extinction, yes, the seas will rise as will the temperature. I am not a specialist on weather patterns, but I feel that if the heat rises so does the rate of evaporation, which in turn creates clouds and rain which would help the temperature level off, at least by a little. I agree Yellowstone will eventually erupt, however I do believe that if the situation becomes dire enough, people would find a way to release the pressure gradually to at least reduce the wide-spread effects of the eruption. As for the ice age, that would be one of the least of humanities worries about a super-volcano eruption. Other greater concerns would be the massive amounts of toxic gas released into the atmosphere. Furthermore, regarding your hopes of colonization of mars, that would be impossible at the current time, due to the massive intra-country conficts going on. Also as a final thought, you speak as if the earth would die, it is a rock in space, it will be fine. It is us who would die.
Our environment has been damaged, yes, but even the worst of scars can fade and eventually disappear, if treated right, our environment just needs some help, and some tlc. There is always a choice, we can still save our environment, terraforming mars is at this point, a mere experiment, and does not mean our environment is falling beyond repair