The basic science behind climate change is actually quite simple.
The story began nearly 150 years ago when Irish physicist John Tyndall discovered ‘carbonic acid’ – today known as carbon dioxide – was one of a number of “perfectly colourless and invisible gases and vapours” to absorb radiant heat.
As Nasa puts it: “There is no question that increased levels of greenhouse gases must cause the Earth to warm in response.” All this does not scientifically prove beyond all doubt that our greenhouse gases, which also include water vapour, nitrous oxide, ozone and methane, are causing global warming.
But the correlation between the two and the evidence of causation first supplied by Tyndall make a compelling argument.
“When we talk about scientific consensus, I would say it’s basically about this [temperature] distribution, it’s not individual predictions,” Professor Palmer told the Royal Society.
But, according to the models, there is a much higher probability of going beyond 2C of warming, than staying below this point, often regarded as when climate change becomes particularly ‘dangerous’.
Professor Richard Betts, a leading Met Office scientist who has also worked on the IPCC's reports, said: “It comes down to how much risk you want to take.
Ironically, the famously impassable Northwest Passage – which claimed the lives of numerous explorers trying to find a new trade route to China – is now so free of ice that people can take a cruise through it on a ship powered by the fossil fuels that help cause global warming.It is thought prudent to restrict warming to a much lower level.Under the terms of the Paris Agreement on climate change, the world agreed to try to keep the temperature rise to "well below 2C ...And, as Professor Palmer also pointed out, there is also “a non-negligible probability of 5C or more, which would be utterly catastrophic”.Models are often the source of derision from climate ‘sceptics’ or ‘deniers’, but they have actually proved remarkably successful when measured against actual observations.