Conservation and Biodiversity

The ocean is taking heat for unchecked climate change, UN report warns

For decades the ocean and cryosphere — the frozen parts of the planet — have been the unsung heroes in our climate crisis, absorbing 90 percent of the world’s excess heat. But now all that warming is catching up to us, a U.N. report out today warns.

The beating the ocean and ice have taken is outlined in full in the Intergovernmental Panel on Climate Change’s (IPCC) Special Report on the Ocean and Cryosphere in a Changing Climate, released this morning in Monaco.

“The world’s ocean and cryosphere have been taking the heat for climate change for decades,” said Kim Barrett, vice-chair of the IPCC, at a press conference early Wednesday. “The consequences for nature and humanity are sweeping and severe.”

The message from the report was clear: We need urgent action on climate change to avert the worst impacts to the ocean, ecosystems and the world we leave for future generations.

Human-caused greenhouse gas emissions, and their effect on planetary warming, have already thrown off the delicate balance of nature, melting ice caps and glaciers and acidifying waters, according to the report. The report also warns that sea ice melt has caused sea levels to rise dramatically, while warmer oceans feeds more intense storms, putting many already-vulnerable communities at ever-increasing risk.

underwater image of seafloor
A special report by the U.N. argues the need for urgent action on climate change to avert the worst impacts to the ocean, ecosystems and the world we leave for future generations.

The report stressed that these changes in climate and the world aren’t limited to some patch of water in the middle of the ocean. Rather, the impacts are far-reaching, influencing the Arctic and the tropics, as well high and low regions, from mountaintops to coastal areas.

“The ocean and cryosphere … might feel very remote to some people, but they impact all of us,” said Hoesung Lee, chairman of the IPCC, at the Wednesday press conference releasing the report. “If greenhouse gas emissions continue to increase, global warming will drastically alter the ocean and the cryosphere.”

The report’s findings, detailed in a 45-page Summary for Policymakers, are striking.

In the last 26 years, the rate of ocean warming has more than doubled. The frequency of marine heatwaves has also doubled since 1982 and are getting more intense every year.

As greenhouse gas emissions are left unchecked, everything gets worse: By 2100, the ocean will absorb two to four times more heat if global warming is limited to 2 degrees Celsius — an almost best-case scenario given our current emissions projections. Beyond 2 degrees, oceans could take in as much as seven times more heat, with devastating impacts on warm-water corals, kelp forests and the distribution and productivity of marine life.

For ice caps and glaciers, the report’s projections are not much better: Sea ice loss from the Antarctic ice sheet tripled in the last ten years, compared to the previous ten years, according to the report. In the mountains, shrinking snowpack and glaciers will put people at risk of more floods, landslides and avalanches, with impacts also on recreational activities, tourism and other cultural assets.

melting glaciers
Sea ice loss from the Antarctic ice sheet tripled in the last ten years, compared to the previous ten years, according to the U.N. report, released Wednesday.

With increases in winter runoffs and earlier spring peaks from melting ice and snow, people will likely face more water shortages during the hottest months of the year, the report warns. Again, these impacts will be felt worldwide by both developed and developing nations. In areas like the American Southwest, for example, more than 40 million people rely on the Colorado River, which is fed by the snowmelt of the Rocky Mountains, for drinking water and irrigation.

Wednesday’s special report is the first time the IPCC has directly assessed the connections between greenhouse gas emissions and extreme weather events like hurricanes and floods. The report points to growing scientific evidence that emissions fuel intense weather events and contribute to the recent phenomenon of more intense and frequent storms, like the Category 5 Hurricane Dorian, which recently ravaged the Bahamas.

From an ecological standpoint, as oceans absorb more carbon dioxide, waters become more acidic, a double-edged sword for marine environments: Acidic waters have decreased levels of oxygen — the report notes the upper layer of the ocean has lost 0.5–3.3 percent of oxygen since 1970 — and also reduce the ability of shellfish species to build protective shells, as acidic waters literally eat away the calcium carbonate that comprises marine ecosystems.

In short, warmer waters force species to adapt, some of which cannot keep up with our current rate of warming. The result is extinction and the loss of species we can never get back.

“One of the saddest things is that some of these species are trying to respond to these changes and can’t,” says Katie Wood, conversation and biodiversity manager at Earth Day Network. “It’s not an economic issue. It’s a morality issue, and as stewards of the earth, we’re failing our planet and its creatures.”

One of the questions addressed this morning by the panel of scientists concerned tipping points, a moment when the effects of climate change are so great that, regardless of emission cutbacks, the climate system begins to work against itself, greatly contributing to climate change in the process.

fisherman casting net
Warming oceans affect fishing, tourism and other cultural assets.

One example of a tipping point is permafrost thawing, which is projected to continue through this century and beyond, the report stated. As permafrost thaws, it exposes centuries-old organic matter to sunlight, releasing greenhouse gases into the atmosphere. Today’s report includes warming pathways that could lead to the release of hundreds of billions of tons of permafrost carbon by 2100. And once permafrost melts it’s unlikely it will ever freeze again, at least not until the next ice age.

Oceans and the cryosphere are almost uncomprehendingly large, but the special report gives perspective on how to join science with policy, knowledge and resources to drive innovative solutions and curb the worst effects of climate change.

The first step is to quickly reduce greenhouse gas emissions, the root of most all these problems.

“The more decisively and earlier we act, the more able we will be to address unavoidable changes, manage risks, improve our lives and achieve sustainability for ecosystems and people around the world, both today and in the future,” said IPCC Co-Chair Debra Roberts at the press conference.

In addition to urgent action, we need “ambitious emissions reductions, together with coordinated sustained and increasingly ambitious adaptation actions,” the report stated.

The report suggested protection and adaptation measures like engineering more climate-resistant infrastructure, alongside more conservation management for fisheries and marine-protected areas and restoration efforts for wetlands and coral reefs.

We also need to consider what used to be a controversial strategy but has since become commonplace: managed relocation, which would require moving families from areas they’ve called home for generations.

As in previous reports, the IPCC stressed the inclusion of indigenous and local knowledge to combat the worst effects of climate change on oceans and the cryosphere. The special report was also the first from the IPCC to formally include education as part of the solutions.

“It’s not an economic issue. It’s a morality issue, and as stewards of the earth, we’re failing our planet and its creatures,” says Katie Wood, conversation and biodiversity manager at Earth Day Network.

The IPCC released the report during the U.N. General Assembly, which kicked off Monday with the Climate Action Summit at U.N. headquarters in New York City. Though the scientists refrained from commenting on actions of world leaders, they did acknowledge the timing of the report and its ability to influence discussions in New York.

The IPCC panel also recognized that people are more aware of the effects of climate change than ever before. This is especially true for young people, who last week led a global climate strike movement that mobilized 4 million people around the world and helped lead to the first-ever U.N. Youth Climate Summit on Saturday. The weekend was punctuated by an impassioned speech by Swedish climate activist Greta Thunberg, calling out government inaction in the face of climate change at the U.N. Climate Action Summit, convened by Secretary-General António Guterres on Monday.

Said Barrett Wednesday morning, “The events surrounding the gathering in New York has certainly demonstrated groundswell of action across the world, particularly by youth, that have been very much supported by the science that we and others provide.”

Perhaps that is the greatest takeaway from the IPCC’s latest special report. For the last thirty years, the IPCC has provided science and statistics that outline the dangers of climate change and unchecked greenhouse gas emissions. While previous generations have ignored these warning signs, young people are heeding reports as ammunition to inform and drive the fight against business-as-usual politics.

Action has been taken around the world, showing that we can cut down on greenhouse gas emissions while still improving society’s well-being. Now we need to scale these actions up to the global level, and quickly. This latest report may serve as additional fuel for the youth movements to further pressure our world leaders into action. And to solve this issue, it will require a unified response from all sectors and generations, as today’s scientists explained.

“We can act,” said Roberts. “We need to mobilize at scale and work together to pull resources at multiple levels across scales.”