ICYMI: Science (Editorial): Climate science speaks: “Act now”
By OSTP Deputy Director for Climate & Environment Jane Lubchenco and Special Presidential Envoy for Climate John Kerry
Last month, one of the most remarkable scientific endeavors on the planet delivered a report to the world. Hundreds of international scientists volunteered thousands of hours to evaluate more than 14,000 scientific publications, respond to over 78,000 comments, and produce a comprehensive scientific assessment to inform government policy-makers. What topic could justify such an intense global effort? The crisis posed by climate change.
For over 30 years, the Intergovernmental Panel on Climate Change (IPCC) has been assessing the science of climate change. Each successive report has provided stronger evidence and deeper understanding, giving governments much of the information they need to develop a response. The fifth IPCC report, released in 2014, catalyzed the Paris Agreement, which aspires to limit the increase in average global temperature to well below 2°C above preindustrial levels, and preferably to 1.5°C.
The Working Group I contribution to the IPCC’s 2021 Sixth Assessment reflects our ever-growing understanding of the physical science basis of climate change, including advances that allow scientists to decipher the fingerprint of climate change in heat waves, heavy rainfall and floods, droughts, and wildfires. These increasingly frequent and severe events are dominating global headlines and stoking public awareness of the economic and humanitarian consequences facing the world because of climate change. The report is full of other noteworthy advancements—more observations of ocean heat waves, improvements in modeling ice sheet dynamics, greater appreciation of the role of short-lived greenhouse gases such as methane, more realistic scenarios of sea level rise, and an understanding of what remains unknown.
Two stark findings command attention. Some changes underway in the ocean and the Arctic are potentially irreversible on human time scales. And the pathway for limiting warming to 1.5°C is narrowing rapidly. These results underscore the urgency of vastly enhancing global ambitions to tackle this threat. Every bit of avoided warming matters.
The United States is confronting this challenge with a bold pledge to reduce emissions by 50 to 52% in 2030. To reach this goal, the Biden-Harris administration is implementing executive actions to cut emissions and bolster resilience to the effects of climate change that are already being felt. This includes mobilizing the leadership from 21 federal agencies and departments to decarbonize the power sector, spur electric vehicle adoption, conserve lands and waters, and protect public health. The White House is also working with Congress to pass the US bipartisan Infrastructure Investment and Jobs Act to develop a new clean-energy economy. At the same time, the nation is investing in research that will guide a rapid transition to a low-carbon future while providing technical and financial assistance to communities most vulnerable to impacts such as heat waves, flooding, and sea level rise. The administration is committed to achieving this unprecedented package of actions by creating jobs and supporting communities that have been historically marginalized and overburdened by pollution and underinvestment.
Because no single nation can solve the crisis alone, the United States is working with other countries to lower their own emissions and improve their resilience while assisting those places already suffering from climate change. The next decade will be critical. To keep the 1.5°C target within reach, all major economies must do more, with immediate, robust, and sustained action to reach net-zero emissions by 2050. This means deploying technological and natural climate solutions, such as conserving and restoring terrestrial and mangrove forests, saltmarshes, and seagrass beds. It means focusing not only on terrestrial activities but also on ocean-based ones such as generating renewable wind, current, and tidal energy; decarbonizing shipping; and protecting existing stores of carbon on the seabed. It means becoming better at helping communities, economies, and ecosystems adapt to climate disruptions.
The world owes a huge debt of gratitude to the hundreds of contributors who labored during a global pandemic to bring the IPCC’s timely findings to policy-makers. Science has delivered the clarity of knowledge. It is now up to leaders in every country—but especially the major economies—to act boldly. This year’s United Nations Climate Change Conference (COP26) in November must be a turning point—the moment when the world heeds scientific findings and collectively rises to meet the greatest challenge of our time.
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