Code Red for Humanity
On Monday, August 9th the Intergovernmental Panel on Climate Change (IPCC) released its 6th annual scientific report on Earth’s climate system. The report has immediately been referred to as “Code Red for Humanity.” Here are several notable highlights from the 3,949-page report:
1. It is unequivocal that human influence has warmed the atmosphere, ocean, and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere, and biosphere have occurred.
After rigorous testing, the scientific community has confirmed with little doubt that human influence has had a dramatic impact on climate change. We are witnessing this with an increase in erratic never-before-seen weather events. The report also confirmed that extreme weather events, including heatwaves, have become more frequent and more intense since the 1950s, while cold events have become less frequent and less severe.
2. Global surface temperature will continue to increase until at least the mid-century under all emissions scenarios considered. Global warming of 1.5°C and 2.0°C will be exceeded during the 21st century unless deep reductions in carbon dioxide and other greenhouse gas emissions occur in the coming decades.
Between 2011 and 2021, Earth’s surface temperature was 1.09°C higher than between 1850-1900. It is expected that we will pass the 2°C marks before the end of the 21st Century. This means that for cities, some aspects of climate change may be amplified, including heat (since urban areas are usually warmer than their surroundings), flooding from heavy precipitation events, and sea-level rise in coastal cities.
3. Natural drivers and internal variability will modulate human-caused changes, especially at regional scales and in the near term, with little effect on centennial global warming. These modulations are important to consider in planning for the full range of possible changes.
With further global warming, every region is expected to experience multiple changes in climate events. The closer we move towards the 1.5°C and then 2.0°C the more pronounced these climate events will become. We are already witnessing some of these outcomes. Coastal areas will see continued sea-level rise throughout the 21st century, contributing to more frequent and severe coastal flooding in low-lying areas and coastal erosion. Extreme sea-level events that previously occurred once in 100 years could happen every year by the end of this century.
4. From a physical science perspective, limiting human-induced global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions. Strong, rapid, and sustained reductions in CH4 emissions would also limit the warming effect resulting from declining aerosol pollution and would improve air quality.
Scenarios have shown that immediate reductions in greenhouse gas emissions lead within years to discernible effects on the global climate. This was noticeable around the planet during the early months of the COVID pandemic when air quality reports around the world were extremely healthy.
To read more highlights and the full report click here.