Next week, global leaders will meet in Poland for this year's U.N. Climate Change conference, referred to as COP24. The meeting could not have come at a more pressing time. In the past few weeks, three significant reports have been published, all of which send a stark warning to humanity about the scale of the threat we are facing.
However, according to Paul Bledsoe, strategic advisor at the Progressive Policy Institute in Washington, and Durwood Zaelke, head of the Institute for Governance & Sustainable Development, even these important papers underestimate the risks of runaway catastrophic climate change.
"Simply put, the sum of the science finds that achieving near-term and deep emissions reductions has become manifestly urgent for the safety of nations around the world," they wrote for The Hill.
The three reports in question are the U.N. Emissions Gap report, the U.S. Fourth National Climate Assessment and the Intergovernmental Panel on Climate Change (IPCC) "Special Report on Global Warming of 1.5°Celsius."
The "Emissions Gap" paper found that current emissions reduction pledges from all countries that signed the Paris Agreement, including the U.S., are nowhere near good enough to stop global temperatures from rising 2 degrees Celsius above pre-industrial levels.
Although a relatively arbitrary figure, most experts take the view that limiting warming to below this level is essential for mitigating some of the worst impacts of climate change (although a host of significant impacts are still likely to occur before then).
According to the report: "Global greenhouse gas emissions in 2030 need to be approximately 25 percent and 55 percent lower than in 2017 to put the world on a least-cost pathway to limiting global warming to 2 degrees Celsius and 1.5 degrees Celsius, respectively."
The National Climate Assessment, on the other hand, looked closely at the impacts that climate change will have on the United States if sufficient action is not taken. The Trump administration has already tried to downplay the findings of the report.
The paper found, based on current predictions, the U.S. economy could take a hit of more than $500 billion annually due to the effects of crop damage, lost labor and extreme weather damages alone. This is almost double the economic impact of the Great Recession, Bledsoe and Zaelke note.
Furthermore, the report suggested that climate change could reduce U.S. GDP by 10 percent by the end of the century. In addition, rising sea levels and extreme weather threaten more than $1 trillion of coastal real estate.
The findings also show that extreme weather events, such as heatwaves, will increasingly become deadlier, while noting that huge costs are already being incurred.
In the southeastern United States, for example: "High tide flooding is now posing daily risks to businesses, neighborhoods, infrastructure, transportation, and ecosystems." The study, notes that the if we can rapidly reduce emissions, then we may be able to avoid some of the worst climate scenarios.
Finally, the IPCC report outlined several strategies that must be undertaken in order to prevent catastrophic warming, including achieving zero carbon dioxide emissions by 2050 and developing means to capture significant amounts of carbon from the atmosphere. Much like the Emissions Gap report, the IPCC paper warns that urgent action is needed to avoid the most severe consequences of climate change.
"Yet, startlingly, even these important studies and ominous warnings are underestimating the existential nature of runaway climate change by failing to consider the self-reinforcing feedbacks that may push the climate system into chaos before we have time to decarbonize the energy system," Bledsoe and Zaelke wrote.
They point to the risk of a "hothouse earth" as described by another major study published in the Proceedings of the National Academy of Science in August. According to this paper, the combined effects of several climatic processes, such as the thaw of permafrost, deforestation and melting sea ice, could push the Earth into a state of runaway warming.
This "hothouse Earth" would experience global average temperatures of 4 to 5 degrees above pre-industrial levels—far higher than the 2 degrees Celsius (3.6 degrees Fahrenheit) limit agreed by the nations of the world at the Paris climate talks.
According to the lead author of the study, Will Steffen from the Australian National University and Stockholm Resilience Center, human-induced global warming of 2 degrees Celsius may trigger other Earth system processes, often referred to as "feedbacks," which can drive further warming—even if we stop emitting greenhouse gases.
"There is a risk that feedback processes intrinsic to the Earth System could form a "tipping cascade", in which the feedbacks act like a row of dominoes," Steffen told Newsweek. "Such a cascade would very likely take the trajectory of the Earth System out of human control and towards much hotter conditions that we call "Hothouse Earth.'"
Despite this dire outlook and the refusal of the Trump administration to acknowledge the seriousness of the situation at hand, Bledsoe and Zaelke say there is "still time to prevent the worst."
"This urgency must begin at the U.N. negotiations next week," they wrote. "But American citizens and those around the world must put our leaders on notice—act rapidly to prevent climate catastrophe, or we must find leaders who will."