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Intergovernmental Panel on Climate Change

As I write this, it is difficult to look away from news that conveys the horrors of war, which are immediate, malevolent, and devastating. The immediacy of this may have overshadowed another item in this month’s news—the release of the IPCC’s 2022 report. It may not seem as urgent a problem to many people, but it is already causing harm to millions of people and will continue to devastate more. IPCC assessments are written by hundreds of leading scientists worldwide, who volunteer their time and expertise. They enlist hundreds of other experts as contributing authors, to provide complementary expertise in specific areas.

The report lays out the tremendous costs for humanity. Among them are: food and water insecurity, increased adverse health impacts, removal of livelihoods, destruction of people’s homes, and the resulting displacement of masses of people. In addition, it details the impacts of increases in natural disasters, including drought in some areas and flooding in others, heat extremes, and increased wildfires.

This sixth assessment by an international group of scientists and experts also focuses on ecosystems and biodiversity more than in previous reports. Researchers, 270 of them from 67 countries, analyzed 14,000 scientific publications to write up the report. Due to their analysis of actual data that has been tested for statistical significance, the authors were able to use terms like “high confidence.” Here’s just a sampling of problems highlighted in the report:

  • Climate change has caused substantial damages, and increasingly irreversible losses, in terrestrial, freshwater, and coastal and open ocean marine ecosystems (high confidence).
  • The extent and magnitude of climate change impacts are larger than estimated in previous assessments (high confidence).
  • Widespread deterioration of ecosystem structure and function, resilience and natural adaptive capacity, as well as shifts in seasonal timing have occurred due to climate change (high confidence), with adverse socioeconomic consequences (high confidence).
  • Approximately half of the species assessed globally have shifted polewards or to higher elevations (very high confidence).
  • Hundreds of local losses of species have been driven by increases in the magnitude of heat extremes (high confidence). Mass mortality events have occurred on land and in the ocean (very high confidence), including the devastation of kelp forests (high confidence).
  • Climate-caused local population extinctions have been widespread among plants and animals, detected in 47% of 976 species examined and associated with increases in hottest yearly temperatures (very high confidence).
  • Risk of extinction is even greater for endemic species. “~100% on islands, ~84% on mountains, ~12% on continents (high confidence), and ~54% in the ocean (notably the Mediterranean) (low confidence) are projected to be threatened with extinction due to climate change.”
  • Marine heatwaves are causing “abrupt shifts in community composition that may persist for years (very high confidence), with associated biodiversity loss (very high confidence), collapse of regional fisheries and aquaculture (high confidence), and reduced capacity of habitat-forming species to protect shorelines (high confidence).”
  • “Ecosystem services that are at threat from a combination of climate change and other anthropogenic pressures include climate change mitigation, flood risk management, food provisioning, and water supply (high confidence).”

The report determines that protection for biodiversity and natural ecosystems is essential. For example, ecosystem health secures resources such as freshwater, and coastal habitats shield against the effects of storms. Multiple lines of evidence indicate that to maintain the resilience of ecosystems, we need “effective and equitable conservation of approximately 30% to 50% of Earth’s land, freshwater, and ocean areas.”

Unfortunately, the harms caused by climate change are accumulating much more quickly than scientists had predicted in earlier reports. The longer it goes unchecked, the more impossible it becomes to stop it.

We must act now to swiftly reduce emissions of carbon dioxide, methane, and other greenhouse gases.