It is not simply global warming. This is something that Magdoff and Foster make very clear throughout What every environmentalist needs to know about capitalism: the full extent of the ecological crisis has to do with the concept of “planetary boundaries”.In this view, there are nine thresholds of the Earth system as we know it (which, more or less sustain human life):1) climate change;2) ocean acidification;3) stratospheric ozone depletion;4) the bio-geochemical flow boundary (the nitrogen and phosphorous cycles);5) global freshwater use;6) change in land use;7) biodiversity loss;8) atmospheric aerosol loading; and9) chemical pollution.As Magdoff and Foster explain: “Staying within each of these boundaries is considered essential to maintaining the relatively benign climate and environmental conditions that have existed during the last 12,000 years (the Holocene epoch)” (p. 13). According to the science, reported by Magdoff and Foster, we have already crossed three of these: climate change, biodiversity and the nitrogen cycle. A number of others are in danger of being crossed in the near future: ocean acidification, global freshwater use, change in land use and the phosphorous cycle.
Read the whole review of What every environmentalist needs to know about capitalism by Fred Magdoff and John Bellamy Foster at Energy Bulletin, A `realistic’ answer to the ecological crisis by Liam Flenady.
This is a list of negative externalities, and as such, costs that are socialized. This masks the true economic cost of many things, especially carbon-based energy. It's not only long terms effects like global warming that are building; it's also dangerous levels of environmental pollution that are affecting everyone now, especially those who are living it cities and their environs.
The basic argument is that when the negative externalities are accounted for in true cost, present day capitalism is unsustainable economically, just as the environment is unsustainable physically.