Understanding Global Warming of 1.5°C

We are facing the greatest environmental challenge of our generation. Many of the world’s biggest challenges, from poverty to widespread biodiversity loss, are being made more difficult by climate change.
As further affirmed in the IPCC Fifth Assessment Report (AR5), human influence on climate has been the dominant cause of observed warming since the mid-20th century as the global average surface temperature warmed by 0.85°C between 1880 and 2012. If global warming continues to increase at the current rate, it is likely to reach 1.5°C between 2030 and 2052.  In fact, 1.0°C of global warming above pre-industrial (1850-1900) levels was reached in 2017-2018.

Impact of 1.5°C or 2°C Warming

The IPCC Special Report on Global Warming of 1.5°C (SR15) underscores that meeting a 1.5°C (2.7°F) target is possible but would require deep emission reductions and rapid, far-reaching and unprecedented changes in all aspects of society . It also finds that “limiting global warming to 1.5°C compared with 2°C would reduce challenging impacts on natural ecosystems, human health, and well-being” and that a 2°C temperature increase would exacerbate diminishing Arctic sea ice, rising sea levels , and extreme weather/climate events, and second-order impacts, such as coral bleaching , and degradation of ecosystems, among others. There would be increased risks to health, livelihoods, food security, water supply, human security, and economic growth. 
Impact vectors include reduction in crop yields and nutritional quality. Livestock are also affected with rising temperatures as reflected by the changes in feed quality, incidence of diseases, and limited water resource availability. Further, risks from vector-borne diseases like malaria and dengue fever are also projected to increase. 
Limiting global warming to 1.5°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.