Half a degree of extra warming: so much that matters

In order to avoid dangerous climate change, temperature rise should be limited to one and a half degrees. The Glasgow climate conference was the last and best hope to keep that goal at your fingertips, the chairman said at the opening. With the end of the climate summit, there is still a threat of warming from 1.8 to 2.3 degrees.

That‘s bad news for millions of people. They will face increasingly extreme heat waves, floods, wildfires and drought over the next few decades.

Half a degree more or less can make up a lot. The UN climate panel IPCC identified the difference between one and a half and two degrees in practice in 2018. Below are some of the conclusions of the IPCC report and other scientific studies.

See for yourself what difference makes one and a half or 2 degrees of warming:

You can see: half a degree of extra warming has major consequences. The Paris Climate Agreement (2015) therefore aimed at keeping the rise in global average temperature well below two degrees (compared to the pre-industrial era) and to make efforts to limit warming to one and a half degrees.

That ‘border‘ of one and a half degrees didn’t just end up in the climate agreement, says climate researcher Heleen de Coninck of TU Eindhoven. That one and a half degrees were under pressure from small island states who saw that they would completely disappear at two degrees of warm-up and thus lose all their land.

That is an infringement of international law because every country has a right in its own territory. That‘s a very strong argument.

In addition, the hope that a reduction in temperature rise to one and a half degrees in other areas is also significantly reduced the impact of climate change. De Coninck: One example is the disappearance of coral reefs. They die out about all the way with two degrees of warm-up. At a degree and a half, you might have a quarter left.

After the one and a half degrees entered the Treaty of Paris, the UN climate panel IPCC was commissioned to investigate what that warming would mean for the world. The IPCC released the special report in 2018. The consequences of one and a half degrees of warming proved so profound that the report raised the question of how safe the ‘old‘ two-degree border was still. Since then, international pressure has increased to reduce warming to one and a half degrees.

Very big consequences

The Coninck was one of the main authors of the report. If the world keeps the temperature rise below one and a half degrees, it could prevent so-called tipping points, she says. In the poles, warming is going harder than in temperate areas. A North Pole without sea ice occurs at two degrees of temperature rise every ten years and at one and a half degrees every hundred years. The melting can pass a tipping point somewhere between one and a half to slightly above 2 degrees. That can have a huge impact on sea level rise.

So every reason to stay below one and a half degrees. But we don’t seem to make it. The most recent analyses show that with the commitments made by countries by 2030, warming will reach 2.4 degrees in 2100. If countries really announced the new plans and intentions they made at the climate summit, that would save 0.1 degrees of warming.


we count all (mostly vague) promises of countries about the distant future (for example, about net zero emissions in 2050, 2060 or 2070), the world is still heading towards a temperature rise of 1.8 degrees. Thus, while the climate summit closed with a call for countries to come up with new plans and promises accelerated, warming of two degrees (or more) seems more plausible than limiting that warming to one and a half degrees.

De Coninck: You‘re talking about hundreds of millions more people who have to deal with less agricultural yield. And with more water stress and stronger heatwaves in such a way that you can’t live, especially in cities.