Long story short. I'll try to compress all facts and logic to the few sentences.

The main thing they don't tell you about climate change and greenhouse effect is that the grow of mean temperature is not the only result of greenhouse. You also get huge reduction of temperature gradient between day and night, winter and summer and across the globe. We already have local greenhouses in tropic forests. The overall gradient is less than 10 Celsius. At the same lattitudes, where are no greenhouse you get ... deserts, with temperature gradients more than 60 degrees.

Overall, if you have -10C to +40C overall gradient, with mean temperature +15C, really you would not get -5C to +45C hell if mean temperature will rise for 5C. You probably will get something like +10C to +30C, that is definitely much better than current -10C to +40C.

Earth already had greenhouse climate in the past multiple times. Eocene, last one, is a good example. There was 1000-2000 ppm CO2. Planet was really green from pole to pole and had mild warm climate everywhere. Eocene is age when mammals developed. In the memory of that we keep temperature and humidity in our houses at values exactly equal to that of eocene. Check the paleontology studies, you will find a lot of interesting stuff, including temperature charts.

Warm greenhouse periods last much longer than ice ages. Every Ice age was unnatural for the Earth, and was a result of some catastrophic event. Extinctions happen only when ice ages began. Return to normal greenhouse climate always lead to evolution and life diversity on the planet. Sea levels was not high in eocene, say Antarctic continent had 25% more territory above sea level than now. They just forgot to tell you, that plants is 80-90% is water, so the water from melted ice will also go to the mass of endless forests and disappeared deserts, and not only for sea level rise. Sea level could be even lower than now, as many eocene studies show.

As the result of global warming we will get literally green planet, with moderate climate everywhere. No drinking water problems, less energy for heating and cooling, endless lands suitable for agriculture, no hunger, more flora and fauna diversity, we even will get rid of all that damned seasonal flus, because there will be no winter. How this could be bad? And for whom?

So, the question is - why all that ecologists fighting with climate change leaded by well known "philanthropists" want Earth stay half dead, like now? Why they try to stop the natural process of exit from ice age happened on Earth multiple times, that will give us endless new territories with pleasant climate where humans, animals and plants could live without constantly fighting with climate? Why that "warriors for the green Earth" spend all their efforts to prevent Earth from becoming literally green from pole to pole? Why they need us to survive on the half dead planet with very few comfort spots over planet?