“The cumulative scientific evidence is unequivocal: Climate change is a threat to human well-being and planetary health. Any further delay in concerted anticipatory global action on adaptation and mitigation will miss a brief and rapidly closing window of opportunity to secure a livable and sustainable future for all.”
These words are taken directly from the United Nations Intergovernmental Panel on Climate Change’s latest report, published this past February. Covering 3,676 pages, 270 of the world’s top scientists analyzed over 34,000 scientific studies to make their conclusions. Every word was reviewed and unanimously approved by 195 countries. This second installment of the United Nation’s three-part series in the Sixth Assessment Report emphasizes the impacts of our warming world on humanity and the environment. The report preceding it, published last August, highlighted the “unequivocal” scientific agreement of how the burning of fossil fuels is causing the planet to warm. This most recent report outlines what can and must be done in response to our warming world by regional and world governments, something which they have thus far fallen short on.
The report opens by describing how negative impacts from global warming are happening much faster than scientists previously thought. The improvement of climate science over the last decade now allows the attribution of how individual storms, wildfires, and heatwaves are both more frequent and intense due to rising global temperatures. Social scientists, epidemiologists, and economists have all observed strong connections between increasing average temperatures and adverse effects on human health and well-being. We are fast approaching a precipice of even worse repercussions, as more severe consequences are occurring quicker and at lower levels of warming. These impacts affect everyone, but vulnerable populations and ecosystems are the most at risk and are already suffering.
Environmental ramifications of climate change are already being observed across all ecosystems. The report describes how heat waves, droughts, floods, wildfires, and disease outbreaks are significantly worsening globally, including in North America. Oceans, mountain forests, rainforests, wetlands, and polar regions are all vulnerable and unable to adapt to these rapid changes of increasing average temperatures. Delicate coral reefs and rainforests initially seemed to handle warming moderately well, but recent studies show they are overwhelmed with current warming levels and beginning to die-off in mass. When temperatures change too rapidly, plants and animals do not have enough time to evolve, forcing them to go extinct or migrate to cooler (but not cool enough) climates where they are less suited to survive. As a result, many extinctions today are directly linked to climate change and compounded by habitat loss. The report projects that if significant action to prevent further warming is not taken soon, 18% of all terrestrial species will face extinction.
While some environmental changes are irreversible, the report warns that their continued degradation is even more concerning. Oceans, tundra, and forests all store large amounts of carbon dioxide, but warming conditions reduce their carbon uptake and cause some ecosystems to begin emitting more greenhouse gasses than they store. Current levels of warming have begun melting permafrost, drying out peatlands, acidifying oceans, and damaging forests through droughts and insect outbreaks. Reducing the amount of greenhouse gasses these ecosystems store increases their concentration in the atmosphere, leading to more warming. Parts of the Amazon rainforest and tundra across North America and Siberia are currently emitting more carbon dioxide than they store. Simultaneous stressors from increased heat waves, droughts, and floods compound ecosystem pressures and cause cascading impacts that are nearly impossible to manage. Humans can control their own actions, but not the biosphere. The report warns that current ecosystem impacts will continue to worsen and become impossible to reverse if widespread global action is not taken soon.
Humans depend on ecosystem stability to survive; current and future changes have already directly and indirectly impacted human well-being. The report finds that 40% of the world’s population (3.6 billion people) is actively at severe risk from climate change. More frequent and intense extreme weather events (like wildfires and floods) expose many to resource deprivation, displacement, suffering, and death. Agricultural production has been declining since 1961 from worsening droughts and heatwaves, increasing malnutrition, and food scarcity. The report specifically outlines how pregnant women are at greater risk due to climate change. Other health impacts include exacerbated respiratory and cardiovascular disease from wildfire smoke and the long-term mental trauma and terminal health issues stemming from surviving weather disasters. A large amount of focus is given to the dangers of heatwaves and high temperatures that kill and make hundreds of thousands of people sick. In the United States, heat is the number one weather-related killer.
A repeated and important point this report returns to is that the repercussions of climate change affect everyone, but not equally. Socially vulnerable and marginalized populations, like the poor, the young, the old, indigenous peoples, and ethnic minorities are disproportionally at greater risk. In the United States, poor people and people of color are most likely to live in dense urban areas with little green space or access to support systems, exposing them to more significant risks from heatwaves and extreme weather events. Globally, poorer regions and those with more violent conflict are identified as being the least resilient. Vulnerable populations are 15 times more likely to die from floods, droughts, storms, and malnutrition that have been exacerbated due to climate change. Hotter conditions, sea-level rise, and more frequent and severe extreme weather events are driving massive migrations and are only projected to worsen. Ecosystem degradation directly impacts vulnerable populations relying on them to meet basic needs, who are also less able to relocate. Often, these groups have contributed the least to climate change but are suffering the most, something profoundly unfair. The report calls out world leaders for their collective lack of policy on protecting and supporting those most vulnerable to the climate crisis.
In 2015, the Paris Agreement set the goal to limit average warming to 1.5 °C (2.7 °F) above pre-industrial levels. This report reiterates the importance of keeping to this goal, as more negative consequences significantly increase above this threshold. Currently, warming levels are at 1.1 °C (2 °F), and there is a 50% chance of permanently exceeding 1.5 °C by 2050, even in the best-case scenario. Every model projection currently indicates surface temperatures will exceed 1.5 °C by 2030 but can eventually return to below this target threshold around 2060 if significant action is taken. The report describes the stark difference between a future that briefly exceeds 1.5 °C and one that remains above it for decades. Temporarily being above 1.5 °C for a couple of years while significantly reducing emissions still avoids some of the worst widespread irreversible changes; models indicate some degree of ecosystem recovery remaining possible. However, staying above 1.5 °C for multiple decades would transform the earth system for centuries, seeing mass extinctions and the permanent loss of ice sheets and glaciers. Failing to keep warming under 1.5 °C has real consequences we do not want to experience.
So, what can we do? Reports from the United Nations are not meant to prescribe specific policy measures but rather to convey scientific agreement on climate change issues. However, this report provides strong scientific consensus on the necessity of two immediate actions: mitigation and adaptation. Previous reports from the Intergovernmental Panel on Climate Change have stressed the need to reduce greenhouse gas emissions to prevent future warming. However, this report acknowledges that governments have thus far fallen short on implementing mitigation actions necessary to slow down warming. It stresses the importance of rapidly reducing emissions, cutting them in half in the next decade, and ceasing all anthropogenic carbon dioxide releases into the atmosphere by 2050. While recognizing the negative climate impacts already happening, the report focuses more on preparing better adaptation measures. Increasing resiliency to current and future changes prepares humans to live in an unavoidably hotter world with more severe and extreme weather events and numerous threats to health and wellness. Adaptation has always been called for in previous reports, but now the focus is equal between adaptation and mitigation, as both are undeniably required to prevent further damage and suffering.
Acknowledging the current impacts of climate change elevates the urgency of preventing more severe warming in the future. This report highlights natural ecosystems’ vital role in mitigation and adaptation. Restoring and preventing further ecosystem degeneration protects species from extinction while reducing warming through the natural storage of greenhouse gasses. Carbon capture and sequestration technology will be an essential component in reducing and keeping emissions below 1.5 °C, but no amount of technology will be able to restore permanently destroyed ecosystems. Protecting and promoting the biological resiliency of vulnerable ecosystems reduces emissions and aids in ensuring the health and well-being of humans. The report urges that we must work with nature, not against it.
Estimates suggest that repairing damaged ecosystems, like wetlands, forests, and coastal mangroves would prevent billions of people from suffering climate change-related illness, poverty, displacement, and death. Protecting natural systems also aids in avoiding maladaptation—practical but short-term solutions that are unviable in the long run. For example, increasing groundwater irrigation to fields combats drought but is not feasible in the face of prolonged and frequent droughts. Sea walls protect cities from sea level rise but destroy coral reefs that also protect coastlines. The report warns against adaptations that fail to consider the long-term effects of warming, as maladaptation only serves to increase vulnerability and exposure to risks. Scientific consensus estimates that “effective and equitable conservation of approximately 30% to 50% of Earth’s land, freshwater, and ocean areas” will be needed to adequality protect natural systems. A balance must be struck, as, ultimately, the best adaptation is mitigation. We are already facing dangerous and unavoidable consequences from climate change, but humans are not powerless in this situation. Our actions got us into this mess, and they have the potential to get us out of it.
To recap, the impacts from climate change are much worse than previously thought, and there is not much time left to meet current climate goals. The most severe consequences can still be avoided but require rapid global cooperation. Vulnerable populations are the most at risk, and community resiliency needs to be improved through long-term and flexible adaptation strategies. Simultaneously, greenhouse gas emissions must be significantly reduced in the next eight years and ultimately stopped by 2050. While technology continues to advance, the restoration and protection of natural ecosystems and biodiversity are essential to preventing future warming and protecting human health and well-being. The window of opportunity is small and shrinking every day, but we can still rise to the challenge.
Read the full report, summaries, and supplementary materials here.
Additional reading:
- Amid troubling UN climate report, Texas ecologist says we have to act fast to adapt to a warming planet(Texas Standard)
- Climate change already worse than expected, says new UN report (National Geographic)
- Climate change is hitting the planet faster than scientists originally thought (Nature)
- Climate change is killing people, but there’s still time to reverse the damage (NPR)
- From drifting to action — Key takeaways from the IPCC report on Impacts, adaptation, and vulnerability(GreenPeace)
- Silver Linings From The UN’s Dire Climate Change Report (NPR)
- What the latest sobering un climate report means for Texas (Texas Signal)