It is not so much climate change that is the problem. It is the rate of change seemingly in step with the accelerating CO2 content of the atmosphere that is of concern. Essentially fossil sunlight is being burnt off by humans at a rate ever increasing since the start of the industrial revolution and the subsequent explosion of the oil industry.
In essence more CO2 equals more energy equals more extreme events equals a potentially precarious future for humans.
That is the bare bones of the argument reduced to the lowest common denominator. Take it or leave it-the true answer is just down the road and shortly coming to a neighbourhood near you.
The climate models may be inaccurate, the details may be disputed but sufficient ecosystems show sufficient disruption over a short timescale for many to be increasingly concerned. The climatic quasi equilibrium that enabled mankind to raise crops, form communities and explode like a rash over the planet over the last few thousand years may be coming to an abrupt end.