The fundamental problem facing humanity today is catastrophic climate change brought on by runaway greenhouse gas emissions. The relatively narrow band of climatic conditions within which we can function has been destabilised. As average temperatures rise extreme weather events are increasing (cyclones, floods, heat waves and droughts) and ocean levels look like rising dramatically, potentially making refugees of millions of people. The very survival of the human race has now been called into question. This pamphlet provides a clear analyisis of what is happening and its prime cause — the rapacious capitalist system which subordinates all human needs to its drive for profit. Only the replacement of capitalism with socialism will enable the overcoming of the crisis. An appendix by the noted Marxist writer John Bellamy Foster convincingly gives lie to claims that Marx and Engels were not sharply aware of humanity’s dependence on nature and that Marxism lacks a clear ecological dimension.