There are many reasons why life on Earth as we know it is possible. For example, the Sun, which is half way through its 10 billion or so star life span, is in its most stable phase; overall the Earth has a stable orbit around the Sun; and the Earth, which on average is about 93 million miles from the Sun, is neither too close to the Sun, as is Venus, nor too far, as is Mars, to support life. We owe our very existence to our unique location and time in the Universe and the overall environmental conditions on Earth.
In the Cenozoic Era, about 65 million years ago, there was no ice on the planet, the sea level was about 240 ft higher than today, and Earth's CO2 level was about 1000ppm (parts per million). Today the CO2 level is 387ppm and climbing. It is estimated that in order to combat global warming, and in turn climate change, the CO2 level must be reduced or turn back to 350 ppm. This, although necessary, will not be easy to do. The sooner the world population does this, however, the more likely it is that we (people of the world) and our grandchildren will survive this dilemma, but, we must act soon and with great determination. Next to thermal nuclear war, climate change is the elephant in the room.
For the most part, the Earth's climate for the last 2000 years or so has been fairly stable. This stability, however, is changing as we enter into the first human-caused global-warming phase characterized by the steady atmospheric increase in green-house gases, such as the most dominate one over which humans have control, carbon dioxide (CO2). For example, CO2 atmospheric levels have increased to the point not seen on our planet in over 160,000 years.
Associated with this CO2 increase is the lock-step increase in Earth's average temperature, or global warmth, due to Earth's green-house effect. Global warming (GW) is the increase over time of global warmth, as we are experiencing now, otherwise, there is global cooling (GC) if global warmth decreases over time. It is GW (or GC) which in turn, causes or drives climate change. At this time, GW is driving our climate change (CC).
One of the most important aspects of GW is that even seemingly modest increases in global temperatures can drive or cause major and disastrous climate-change conditions, such as, a more frequent number of hot days, prolonged drought, sea level rise, floods, wild fires, species die off, species migration, an increased frequency and strength of storms including hurricanes, typhoons, and tornadoes, and the emergence of new animal diseases, plant diseases, and pests.
As time passes, four of the major GW-driven climate-change impacts on humans will be: availability of water, stability of food production, sea level rise, and the destruction of forests by wild fires. Climate change is happening now and will continue to happen. The only questions are: For how long and at what rate will it occur? How bad will CC get? Can we do anything about it? Will we do anything about it?
The last question is easy to evaluate since it breaks down into four fundamental substatements where one
of which can only
happen because GW is happening or it's not and we take action or don't:
The only sub-statements in this analysis that will be disastrous for us is the last one (d), which unfortunately is the path our Congress is on at this time thanks in large part to the fossil fuel (oil and coal) industry and their misinformation and lobbying efforts, the apathy of the general public, and the Tea Party, for note that, in the 2010 elections more than half of the newly elected Republicans did not believe in Global Warming. This is a tragedy since the Science is so overwhelmingly clear that GW is occurring and we know why: human activity caused CO2 emissions.
At this point in our industrial and technological development, the Earth is ours to ignore or do with as we wish at our own well being or peril. One thing is clear, in 1000 years the Earth will still be in its stable obit around our stable star, it just not clear whether or not humans will exist to continue enjoying the ride.