The IPCC sixth assessment report: Observed and projected impacts

On the 28th of February this week the second part of the IPCC sixth assessment report (AR6) was released focusing on how climate change impacts the world and the necessary adaptation efforts. 

In the following we will give a brief overview of the observed and projected impacts in the report, whereas adaptation efforts will be discussed in a follow-up blog post. 

Observed impacts

Ecosystems, people, settlements, and infrastructure. Widespread and significant adverse impacts from increased frequency and intensity of extreme weather events such as heavy precipitation events and droughts. 

Terrestrial, freshwater, and coastal and open ocean marine ecosystems. Significant damage and increasingly irreversible losses, whereby the observed impacts are more severe than anticipated in previous assessments. 

Food and water security. Resulting from increased frequency and intensity of extreme weather events, food and water security have decreased, thereby hindering progress on the SDGs regarding, among others, the goal of zero hunger by 2030. 

Physical and mental health. Climate change has increasingly negative effects on physical and mental health because of, among others, increasing pollution and heatwaves. This is particularly true for urban settings. 

Humanitarian crises. Climate change is found to be a reinforcing factor for humanitarian crises when combined with climate hazards such as hurricanes. Moreover, 3.3 to 3.6bn people already live in areas that are highly vulnerable to climate change. 

Projected impacts

Biodiversity loss. Increased frequency and intensity of extreme weather events coupled with continuous warming will bring many terrestrial, freshwater, coastal and marine ecosystems to their limit in terms of resilience and adaptation capacity. Hereby the level of risk depends on current vulnerability, exposure, and socioeconomic capacity to adapt to the changes in the short-term. In the mid to long-term the level of risk increases with the rate of additional warming. 

Water scarcity. Water scarcity will continue to increase in all regions, with pressure on water resources increasing with every additional degree of warming. Moreover, melting glaciers will change river flow in many regions, posing challenges to water management while also reducing water availability. 

Food security. Climate change will put additional pressure on food security through desertification and reduced ecosystem services, particularly in regions that are already highly vulnerable to climate change such as Sub-Saharan Africa. 

Physical and mental health. More frequent and intense extreme weather events such as heatwaves will considerably increase the rate of premature deaths. 

Urban settlements and infrastructure. Many island nations and coastal cities are already highly vulnerable to sea level rise today. This trend will further intensify with some places becoming uninhabitable because the threshold for adaptation capacity is exceeded. 

Displacement. Resulting among others from sea level rise, heat extremes and desertification will displace many more people while aggravating civil unrest.