What happens at a 1.5, 2 and 3ºC increase in temperature?

Updated: Jan 23

We're already at a 1.2C (degrees Celsius) increase in average global temperature, verses pre-industrial levels, and are witnessing the extreme weather associated with it. But, disturbingly, CO2 levels are still rising, and it's terrifying to think of what lies ahead if climate change isn't stopped, or reversed, immediately.

Limiting temperature to 1.5C (verses pre-industrial levels) is seen as a ‘best case scenario' by climatologists, and this, of course, will have even more dramatic impacts on life as we know it. So let's look at what's predicted to happen around the world if global temperature continues to climb.

+1.5C of warming vs now

  • 48cm increase in sea level from melted ice caps, and for every cm rise 1 million people could displaced from their homes [1,2,14]

  • Marine heatwaves that'll destroy ocean life (incl. 80% of coral reefs) [1]

  • Droughts lasting 2 months longer on average [2]

  • 2% more intense rainfall [1,2]

  • Extreme heatwaves affecting 14% of global population once/5 years [2,4,5]

  • Intense EU wildfires covering 41% more ground [1]

  • Reduced maize and wheat crops (falling 5- and 6%, respectively) [2,3]

  • 6 fewer days of winter frost/year in the UK with hotter summers and increased rainfall causing significant river flood damage (1,200% more than now) [1]

It's mind-blowing to think that this is what world leaders are aiming for. The economic and social consequences of this will be huge. Annual flood damage and loss from sea level rise will reach eye-watering amounts, global GDP/capita will be lower, and millions will suffer from homelessness and hunger.

+2C of warming vs now

  • 56cm increase in sea level [1,2]

  • Total coral reef extinction with knock-on effects to all ocean life [1]

  • Ice-free summers in the Arctic Ocean, once per decade, causing Earth to absorb heat from the sun (vs reflecting it with ice) and accelerate warming [6,7]

  • Droughts will last 4 months longer on average [2]

  • 4% increase in rainfall intensity [2]

  • EU wildfires will burn 67% more land each summer [8]

  • 37% of Earth’s population will be exposed to extreme heatwaves once/5 years [2,4]

  • Fewer maize and wheat crops (9% and 4% vs respectively) [2]

  • Northern Europe will become wetter, and flooding will become commonplace [1]

Climate impacts will be unevenly distributed around the globe, e.g. West Africa will see a 753% increase in extreme heat compared to a 187% increase for Northern Asia. [1] In Southern Europe, more than 1/3 of the population will have less water than they need. [1] More people will experience homelessness and hunger. We'll see millions of climate change migrants.

+3C or more of warming

Beyond 2C of warming, planetary ‘tipping points’ (9 in total which include: melting of ice sheets, collapse of the Amazon rainforest and thawing of permafrost) are expected to kick off runaway, permanent climate change.

  • Melting of the West Antarctic ice sheet could spark sea level rise of 1.6 metres or more, reshaping ocean currents, tropical weather systems and polar climates [1]

  • Collapse of the Amazon rainforest would result in dry scrubland that'll affect millions of people and animals in the region, and release of billions of tonnes of CO2 into the atmosphere as trees die and vegetation burns. It'll also reduce rainfall throughout central and southern South America, and alter climate patterns farther afield [9]

  • Thawed permafrost would result in the release of trapped methane, a more powerful greenhouse gas than CO2, directly into the atmosphere accelerating global warming and contributing to the spread of devastating Arctic wildfires [10]

And recent research suggests these thresholds could in fact be much closer to 2C, or may have been breached already. [11,12]

What can we do?!

  1. Change our diet. Consuming fewer animal products is the single best way an individual can reduce their carbon footprint (as well as improve their health and prevent animal suffering) [13]

  2. Save energy. Simple, every day changes have a huge impact if we all make them. Leave the car at home and walk sometimes, put a lid on your pans when cooking to save energy and money, launder at lower temps and be vigilant at turning off appliances and lights when not in use around the home

  3. Don't buy products with palm oil, even it if it's "sustainable palm oil," palm tree mono crops are destroying the Indonesian rainforest

  4. Plant trees. With us, or any other tree planting company. It really doesn't matter, just get involved and help restore nature whilst mopping up carbon in the process

Most importantly do something. Don't be overwhelmed by the facts and have hope. We are not yet consigned to the worst case scenario, and still have time to limit climate impacts. We just we have to act now.


  1. https://apple.news/AURwpkU9JQ9uexp1QFdV6tQ

  2. https://interactive.carbonbrief.org/impacts-climate-change-one-point-five-degrees-two-degrees/?utm_source=web&utm_campaign=Redirect#

  3. https://iopscience.iop.org/article/10.1088/1748-9326/aaba48

  4. (https://climate.nasa.gov/news/2865/a-degree-of-concern-why-global-temperatures-matter/

  5. https://www.ipcc.ch/site/assets/uploads/sites/2/2019/06/SR15_Chapter3_Low_Res.pdf

  6. https://www.nature.com/articles/s41558-018-0124-y

  7. https://www.ipcc.ch/sr15/chapter/chapter-3/

  8. https://www.nature.com/articles/s41467-018-06358-z

  9. https://www.nature.com/articles/d41586-020-00508-4

  10. https://www.thearcticinstitute.org/permafrost-thaw-warming-world-arctic-institute-permafrost-series-fall-winter-2020/

  11. https://www.nature.com/articles/d41586-019-03595-0?utm_campaign=Feed%3A+nature%2Frss%2Fcurrent+%28Nature+-+Issue%29&utm_medium=feed&utm_source=feedburner

  12. IPCC. IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (IPCC, 2019)

  13. https://josephpoore.com/Science%20360%206392%20987%20-%20Accepted%20Manuscript.pdf

  14. https://www.highnorthnews.com/en/every-centimeter-sea-level-rises-one-million-more-people-will-have-evacuate

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