As it happens, the odds may still be in our favour. A new study estimates there's a 64 percent chance that peak global average temperature rise can be kept to below 1.5°C – a crucial threshold we really don't want to cross.
If we couldn't hit that target, scientists and thought leaders told us, we needed to then focus on stopping temperature rises from reaching 2°C above pre-industrial temperatures.
In just a few short years, these goalposts have moved dramatically.
Newer scientific assessments suggest that the consequences of even a 1.5°C global temperature rise will have diabolical impacts on the environment we weren't previously aware of.
In other words, achieving our optimistic goal is something we should desperately be seeking to do, but can it still be done?
Yes, according to climate scientist Chris Smith from the University of Leeds, but only if our efforts to dismantle the machinery of carbon pollution begin right away.
"Our research found that the current amount of fossil fuel infrastructure in the global economy does not yet commit us to exceeding the 1.5°C temperature rise limit put forward by the Paris Agreement," Smith explains.
"We are still within the margin of achieving the scenario the model put forward."
In the new study, Smith and fellow researchers modelled a number of hypothetical climate scenarios, including calculating what might happen if all carbon-intensive infrastructure – including all fossil fuel power plants, factories, and even cars and planes – were phased out immediately.
Of course, never driving your car again (or using electricity derived from burnt coal) is an unlikely, impossible dream. But if the world could bring itself to embrace such immediate changes, hypothetically, the worst effects could be mitigated.
If such a change happened by the end of 2018 (or right away, in other words), the researchers' simulations suggest there's roughly a 2 out of 3 chance we won't hit the 1.5°C temperature rise we're trying to avoid.
"It's good news from a geophysical point of view," Smith told The Guardian, while acknowledging the immense sacrifice it would require.
"We are basically saying we can't build anything now that emits fossil fuels."
While it's unrealistic to hope the world will be able to forgo its entire reliance on fossil fuels so instantaneously, the study suggests even a minor delay in making these adjustments will come with drastic consequences in terms of our ability to realise the 1.5°C goal.
"Delaying mitigation until 2030 considerably reduces the likelihood that 1.5°C would be attainable even if the rate of fossil fuel retirement was accelerated," the researchers explain in their paper.
In short, everything is riding on our actions within weeks, months, and years – not decades or longer. We just don't have that sort of time.
Even if we can't come close to bringing about the radical, immediate societal changes this research proposes, we need to absorb the disastrous ramifications of not doing so – and get up to speed on saving the planet as quick as we can.
"Whether it's drilling a new gas well, keeping an old coal power station open, or even buying a diesel car, the choices we make today will largely determine the climate pathways of tomorrow," says carbon management researcher Dave Reay from the University of Edinburgh, who wasn't involved with the study.
"The message of this new study is loud and clear: act now or see the last chance for a safer climate future ebb away."
The findings are reported in Nature Communications.