James Hansen declares climate change a moral issue on par with slavery. I think it's more profound, since the future of humanity is at stake. Slavery can be halted quickly and its effects reversed in a few generations. Once we render the planet uninhabitable for everyone, humanity's trajectory is uncorrectable. Even if we somehow manage to stop our destructive actions, feedback mechanisms will have been kicked into place and irreversible damage done such as species extinctions.
Hansen told the Guardian that the latest climate models had shown the planet was on the brink of an emergency.
"The situation we're creating for young people and future generations is that we're handing them a climate system which is potentially out of their control," he said.
I use the term "Climate Destabilization" rather than "Climate Change" because it's more accurate (less vague and less ambiguous) and carries an appropriate normative force.