The science of climate change is by now quite clear and generally well understood. In brief, CO2 and other greenhouse gases trap the sun’s heat, raising the average temperature of the atmosphere and (indirectly) the oceans. We have emitted so much extra CO2 since the Industrial Revolution (and especially since 1950) that we are on course for dangerous droughts, heat waves, sea-level rise and species extinctions – up to and including mass starvation and massive dislocation of human populations. For authoritative summaries of the science, with links to further information, visit these pages by CSIRO, the BoM or NOAA.
The science has been denied and obscured by vested interests, almost since it was first discovered. Those vested interests, overwhelmingly fossil fuel producers, have campaigned successfully to cast doubt on the science and to corrupt governments, with the object of slowing our vital move away from fossil fuel usage. At this stage, it is fair to say that anyone directly involved in the debate, whether scientist or politician, who denies the science is either lying or incompetent, and to call them a ‘denialist’. For more on denialism, try Skeptical Science and Desmogblog.
A glimmer of hope arose with COP 21 in Paris in December 2015, when world leaders met and agreed to work to keep the increase in global temperatures to less then 2 degrees C - and strive to keep it below 1.5 degrees C (read this Ecowatch article for a review of what the Paris meeting achieved and what is still to be done). Sadly, within weeks of this agreement, the Federal and Queensland governments approved what would be the largest coal mine in the southern hemisphere and the third largest in the world. Despite all the Paris rhetoric, our work as a community is not over.
As a community we need to slow down climate change as quickly as possible and then move towards stopping and even reversing it. Emissions reduction is the crucial strategy here - getting out of fossil fuel through demand reduction (efficiency) and a shift to solar and wind power; one current focus is starving coal mining companies of funds through divestment initiatives, e.g. Kittens for the Reef, a NQCC project. At the same time, we need to work on adaptation and other aspects of mitigation; see this UN Environment Programme page for more.