The United Nations formed the Intergovernmental Panel on Climate Change (IPCC) to inform national governments about the science and potential impacts of climate change. Humans have heated the planet by roughly 1.1°C since the 19th century, mainly from burning coal, oil, and gas for energy. 

The consequences of global warming can be seen this summer alone, with heatwaves across the US and Canada, floods devastating Germany and China, and wildfires are raging out of control across the world. Unless immediate, rapid, and large-scale action is taken to reduce emissions, the report says, the average global temperature is likely to reach or cross the 1.5°C warming threshold within 20 years. 

Some key points from the IPCC report:

• Global surface temperature was 1.09C higher in the decade between 2011-2020 than between 1850-1900.

• The past five years have been the hottest on record since 1850

• The recent rate of sea level rise has nearly tripled compared with 1901-1971

• Human influence is "very likely" (90%) the main driver of the global retreat of glaciers since the 1990s and the decrease in Arctic sea-ice

• It is "virtually certain" that hot extremes including heat waves have become more frequent and more intense since the 1950s, while cold events have become less frequent and less severe

While this report is more clear and confident about the downsides to warming, the scientists are more hopeful that if we can cut global emissions in half by 2030 and reach net zero by the middle of this century, we can halt and possibly reverse the rise in temperatures. 

Reaching net-zero involves reducing greenhouse gas emissions as much as possible using clean technology, then burying any remaining releases using carbon capture and storage or absorbing them by planting trees.

According to a draft of an upcoming IPCC scientific report, some lifestyle changes could also cut emissions twice the size of Brazil’s current emissions by 2030. Changes include heating and cooling set-point adjustments, reducing appliance use, shifting to human-centered mobility and public transit, reduced air travel, and improved recycling. The draft IPCC found that individual behavior change in isolation cannot reduce greenhouse gas emissions significantly, but individuals can contribute to overcoming barriers and enable climate change mitigations. 

The full second report, set to be released in 2022, will detail how climate change might affect human society, such as coastal cities, farms, or health care systems. A third report, also expected next year, will explore more fully strategies to reduce greenhouse gas emissions and halt global warming.