Over two decades ago, international scientific consensus established that emission of greenhouse gases, due to human economic activities, had increased the average global temperature and that, without immediate action, that temperature would continue to rise.
The consensus asserted that inaction would result in severe climate disruptions to which living systems would not be able to adapt.
Since then, greenhouse-gas emissions have continually increased, exceeding the safe level of 350 parts per million (ppm) of carbon dioxide and, this year, exceeding 400 ppm.
Ongoing research in climate science has yielded predictions that are more often too cautious and conservative than they are accurate in terms of the expected effects.