In September the world’s heads of state, global CEOs and more will convene in New York as part of the UN Climate Action Summit to discuss action to meet the 1.5°C target. In the run up to the event, we will walk you through everything you need to know about the Summit, 1.5°C (what happened to 2°C?!) and what business leaders, countries, and society at large can do about it. 

Whether you are aware of the upcoming U.N. Climate Action Summit in New York, the IPCC, or even just Greta Thunberg’s Instagram account, you have probably heard about preventing 2°C or even 1.5°C of global warming. The Climate Action Summitin September  has a strong focus on 1.5°C, but does half a degree matter? Will it be the end of the world if our summer holidays are 2°C rather than 1.5°C hotter? Spoiler alert: Yes. To give you a preview, half a degree is expected to exacerbate crop failures, forest fires, and flooding, strain economies, and add tens of millions more climate refugees. So apart from an extra lemonade in August, half a degree could make a world of difference.

First things first, when we talk about 1.5°C of warming, we mean the increase in the Earth’s average surface temperature. Another important thing to note is that global rates of warming will not be the same everywhere. In fact, some areas (#northpole) are warming much more quickly than others. Therefore, when someone tells you about 1.5°C of warming, think about preventing the Earth’s average temperature from rising, not necessarily your back garden. What you should also remember about climate change is that it’s not the case that everything up to 1.49999°C is rainbows, unicorns, and free ice cream for everyone. We are already experiencing climate change-related challenges all over the world. But when and why did the international focus shift from 2°C to 1.5°C?

For many years, the focus from the UN has been solely on preventing global warming above 2°C. However, a Special Report from the IPCC (also known as “global rock star scientists”) in 2018 highlighted the now better-understood risks of 1.5°C warming compared with 2°C, and some of the forecasts create more than a little cause for concern. The special report is to a large extent why the international focus and debate has shifted from 2°C to 1.5°C. Here are some pertinent facts that might help to show how crazy the small difference between a 1.5°C and 2°C world could be. 

  • In Northern Europe, a 2°C rise compared with 1.5°C  is expected to mean double the amount of warm weather extremes. Having exceptionally hot days is expected to increase summer fatalities, especially for more vulnerable sectors of society.

 

  • The same goes for thunderstorms and heavy rains. If our planet indeed warms by 2°C, Europe can expect double the amount of rainfall extremes compared with a 1.5°C scenario.

 

  • A 2°C rise compared with a 1.5°C rise is expected to cause an extra 10cm of sea level rise, impacting an extra 10 million people. That’s twice the population of Denmark, for comparison.

 

  • Sea ice-free Arctic years: In a 1.5°C scenario, it is very likely to have one sea ice-free summer every 100 years. At 2°C, the frequency increases to at least once every ten years.That’s a ten-fold increase for half a degree difference.

 

  • Last but not least, while coral reefs might decline by a further 80% in a 1.5°C scenario, they are expected to be almost entirely wiped out in a 2°C scenario. Apart from looking beautiful, they are crucial to marine ecosystems around the world, which 1 billion people depend on for food.

 

These statistics are taken from the 2018 IPCC 1.5°C Special Report and, obviously, they are somewhat simplified. Go to the report to get the full low-down.

It can be difficult to grasp some of the numbers and comparisons between the temperature scenarios, but there are some great visualisations out there that can help. This figure from Vox is one of our favourites, but there are many more, including a fantastic and extensive website by Carbon Brief. The New York Times also did a pretty neat job. 

The trick is to find a statistic or figure that means something to you, wherever you may live, rather than trying to deal with global statistics which can become meaningless numbers. Are you an Amsterdammer? If so then maybe you should be thinking about how sea level rise might affect you and your low-lying family. If you’re living in Australia then perhaps the significant increases in drought might trouble you. Or perhaps your family is reliant on plentiful fish who in turn could be affected by the collapse of coral reefs. Pick your area, find your facts, and then you will see that half a degree truly can make a world of difference.