Ocean Sciences News

Grim Report on Climate Change Impacts on Oceans and Cryosphere

A new report by the Intergovernmental Panel on Climate Change states that bold actions can prevent significantly worse impacts.


A new scientific report provides a dire picture of the impacts of climate change on the world’s oceans and cryosphere and their ecosystems; people who depend on their natural resources; and those at increased risk from sea level rise, extreme weather, and other threats associated with climate change.

The report, released just 2 days after the United Nations Climate Action Summit, is not entirely pessimistic. It also underlines how measures including immediate, ambitious, and coordinated actions to curb greenhouse gas emissions could still limit climate change and its related impacts.

“The oceans and cryosphere, the frozen parts of the planet, might feel very remote to some people, but they impact all of us,” said Hoesung Lee, chair of the Intergovernmental Panel on Climate Change (IPCC), at a 25 September briefing to release its Special Report on the Ocean and Cryosphere in a Changing Climate. The report follows several other recent IPCC special reports, including its report on limiting global warming to 1.5°C above preindustrial levels.

“This report is showing that if greenhouse gas emissions continue to increase, global warming will drastically alter the ocean and the cryosphere,” Lee said. “However, if we reduce emissions sharply, consequences for people and their livelihoods will still be challenging, but they will be potentially more manageable for those who are most vulnerable. The report reveals the benefits of ambitious and effective adaptation for sustainable development. Conversely, there may be escalating costs and risks associated with delayed action.”

The report states, “Enabling climate resilience and sustainable development depends critically on urgent and ambitious emissions reductions coupled with coordinated sustained and increasingly ambitious adaptation actions.”

The report cites other vital measures to address climate change, including education and climate literacy, monitoring and forecasting, financing, sharing of data, addressing social vulnerability and equity issues, and intensifying cooperation and coordination among governing authorities.

Rapidly Changing Oceans and Cryosphere

Among the report’s findings about the oceans is that “it is virtually certain that the global ocean has warmed unabated since 1970 and has taken up more than 90% of the excess heat in the climate system.”

The report also states that over the 21st century, the global ocean “is projected to transition to unprecedented conditions,” with increased temperatures, upper ocean stratification, further acidification, increased marine heat waves, and other factors. The impacts of the changing oceans on people include coastal communities being exposed to tropical cyclones and extreme sea level rise. The acceleration in recent decades of global mean sea level is due to increasing rates of ice loss from the Greenland and Antarctic Ice Sheets, along with continued glacier mass loss and ocean thermal expansion, the report notes.

Findings about the cryosphere are equally grim. “Over the last decades, global warming has led to widespread shrinking of the cryosphere” with mass loss from ice sheets and glaciers, reductions in snow cover and Arctic sea ice extent and thickness, and increased permafrost temperature. The impact of the shrinking cryosphere in the Arctic and high-mountain regions has significantly affected people, with threats to food security and water resources.

Responses from Environmental Groups

Environmental groups applauded the report and the climate change threats that it outlines, and they called for more action to deal with climate change.

Miriam Goldstein, managing director for energy and environment policy and director for ocean policy at the Center for American Progress, said that “the report offers more scientific evidence of the impact of climate change and the urgent need for real solutions.”

George Leonard, chief scientist with the Ocean Conservancy, said that “the world needs to take ambitious climate action now,” including reducing emissions, advancing responsible ocean renewable energy, protecting ecosystems, and preparing for changes to come.

“We Are in a Race Between Two Factors”

“We are in a race between two factors,” IPCC chair Lee said at the briefing. “One is the human ecosystem’s capacity to adapt, and the other one is the speed of impact of climate change.”

Lee said that this report and other recent IPCC reports indicate that “we may be losing in this race.”

He added that “we need to take immediate and drastic action to cut emissions right now, and especially right from the next year, if we want to achieve this carbon neutrality in the mid of the next century.”

—Randy Showstack (@RandyShowstack), Staff Writer

Citation: Showstack, R. (2019), Grim report on climate change impacts on oceans and cryosphere, Eos, 100, https://doi.org/10.1029/2019EO134429. Published on 25 September 2019.
Text © 2019. AGU. CC BY-NC-ND 3.0
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