Bill McKibben, one of the earliest to write about climate change and the founder of [350.org][http://350.org], has a article on the state of play in the New York Review of Books. In it he looks back on what scientists got right with their early modelling…
These climate models got their first real chance to shine in 1991, when Mount Pinatubo erupted in the Philippines, injecting known amounts of various chemicals into the atmosphere, and the models passed with flying colors, accurately predicting the short-term cooling those chemicals produced.
…recalls that the oil companies were well aware of the problem even while they did their best to ensure no meaningful action was taken…
Exxon, for instance, got the problem right: one of the graphs their researchers produced predicted with uncanny accuracy what the temperature and carbon dioxide concentration would be in 2019. That this knowledge did not stop the industry from its all-out decades-long war to prevent change is a fact to which we will return.
…and goes on to point out that we need to do way more than we’ve been doing.
To meet the Paris goal of limiting temperature increases to 1.5 degrees Celsius, the world would need to cut its emissions by 7.6 percent annually for the next decade. Stop and read that number again—it’s almost incomprehensibly large. No individual country, not to mention the planet, has ever cut emissions at that rate for a single year, much less a continuous decade. And yet that’s the inexorable mathematics of climate change. Had we started cutting when scientists set off the alarm, in the mid-1990s, the necessary cuts would have been a percent or two each year. A modest tax on carbon might well have sufficed to achieve that kind of reduction. But—thanks in no small part to the obstruction of the fossil fuel industry, which, as we have seen above, knew exactly what havoc it was courting—we didn’t start correcting the course of the supertanker that is our global economy. Instead, we went dead ahead: humans have released more carbon dioxide since Hansen’s congressional testimony than in all of history before.
The whole article is worth a read to get an idea of where we are currently and the potential for change, from increasing use of renewables to divestments and campaigns to leave fossil fuels in the ground.