The threat of climate change means that for the first time humanity is faced with the very real possibility of extinction. The root cause of the ecological crisis is capitalism's drive to maximise immediate profits above all else.
The UN has estimated that the total cost of conserving tropical forests, reforesting the Earth to an environmentally healthy level, reversing desertification, developing renewable energy and implementing energy efficient practices is about the same as just a few months of global military spending.
This is only one example of why this system is profoundly at odds with a sustainable planet. The exploitation of nature is as fundamental to the profit system as the exploitation of workers.
Capitalist economics treats the air, rivers, seas and soil as a "free gift of nature" to business.
Right-wing economist Milton Friedman said the only social responsibility of business was to make as much money for its shareholders as possible. Most major companies aren't quite so honest. The big polluters spend millions advertising themselves as "green", while they continue to plunder the Earth to keep the shareholders happy.
The market system can't help preserve the environment for future generations because it cannot take into account the long-term needs of people and planet. The competition between individual companies to make a profitable return on their investment excludes rational and sustainable planning.
This thirst for profit prevents pro-capitalist governments from responding rationally to the climate crisis — despite the immense scale of the threat.
Stopping climate change is impossible unless the profit motive is removed from the equation. The crisis poses a big choice. We can continue in the ways of capitalism and an unhabitable planet, or we can start down the democratic socialist path — a path of harmony with nature, grassroots democracy and respect for life.