Extreme weather events like severe heat waves or powerful rainstorms don’t go up uniformly with an extra half-degree, but rise exponentially as the global average temperature increases.
Global mean sea level rise is projected to be around 0.1 metre lower with global warming of 1.5°C compared to 2°C, by 2100. The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C, compared with at least once per decade with 2°C.
Impacts on biodiversity and ecosystems, including species loss and extinction, and irreversible loss of many marine and coastal ecosystems increases, are projected to be much lower at 1.5°C of global warming compared to 2°C.
Insects are almost three times as likely to lose over half of their habitat at 2°C compared with 1.5°C. Of 105,000 species studied, 6% of insects, 8% of plants, and 4% of vertebrates are projected to lose over half of their climatically determined geographic range for global warming of 1.5°C, compared with 18% of insects, 16% of plants and 8% of vertebrates for global warming of 2°C.
The level of ocean acidification due to increasing carbon dioxide concentrations associated with global warming of 1.5°C is projected to amplify the adverse effects of warming, and even further at 2°C.
Climate-related risks to health, livelihoods, food security, water supply, human security, and economic growth would increase with global warming of 1.5°C and increase further with 2°C. Limiting global warming to 1.5°C compared with 2°C could reduce the number of people both exposed to climate-related risks and susceptible to poverty by up to several hundred million by 2050.
The importance of scientists to act
If this already sounds terrifying to you, this is only what’s written in the so-called Summary for Policymakers. Though, in it, some of the biggest effects due to climate change which are described in the full report are omitted, and moreover, from the report, also studies are omitted which imply an even more urgent need for direct action.
That's why it's important to read the whole report and not only the Summary for Policymakers.
Here, it becomes evident, why science is political and must be and why scientists have to have an effect on politicians and shouldn’t stay in their ivory tower.
The single biggest way to have impact on climate change and other environmental crises is through collective pressure on policymakers to actMichael Mann
The science and research is the background providing us with the information of how global warming is affecting the world.
But the IPCC report is the result of many scientists trying to generate a document they all agree on, while afterwards the ‘key results’ were decided upon and put together in a Summary for Policymakers together with the politicians or governments who should transform it into action. But as we know, politicians most of the time don’t follow the general interests, but industry interests and dependencies.
The Summary for Policymakers was approved line by line by governments during intensive discussions before it was presented to the public on October 8.
In the final week of negotiations in South Korea, there were fears the text would be watered down by the US, which Trump wants to pull out of the Paris Agreement, Australia, world’s largest coal exporter, and Saudi Arabia and other oil-rich countries that are reluctant to consider more ambitious emission cuts.