As the New Republic stated in 2014:
The de facto assumption of climate change policy is that the world must limit the increase in global temperatures to 3.6 degrees Fahrenheit (2 degrees Celsius). This is also above pre-Industrial levels and/or are at risk hitting a tipping point. That’s consequently where the impact becomes irreversible.
So the figure dates back to 1975. William Nordhaus, an economist, suggested that more than 3.6 degrees of warming would “take the climate outside of the range of observations. That’s all which have been made over the last several hundred thousand years”.
By the 1990s, 3.6 degrees gained traction in the scientific community. That’s when politics came in through the European Council. They argued in 1996 that 3.6 degrees should be the United Nations’ red line for global warming.
However, it wasn’t until four years ago, at a climate conference in Cancun, Mexico. That was when countries finally committed to “hold the increase in global average temperatures below” 3.6 degrees.
So despite being almost 40 years old, this temperature threshold remains controversial. I mean and for good reason. One: It’s rather arbitrary. Two: It’s unrealistic.
Furthermore think of the idea of staying within 3.6 degrees. I mean global carbon pollution would have to begin coming down in the next decade.
Because this is all according to the United Nations Environmental Program Emissions Gap Report. So the world will have to reach zero net greenhouse gas emissions. All as a result before the end of the century.
In other words, we’re nowhere near where we need to be. Especially as to stay under this target. Pollution continues to rise. As well as global temperatures are already locked in for warming.
That puts the planet two-thirds of the way there. We are now currently around 1.5 degrees above pre-industrial level temperatures; that’s counting the pollution we’ve emitted and will continue to emit in the short-term to medium-term.