The Warming Crisis in our Oceans

The impacts of climate change are already being felt widely and deeply around the world. Since the most recent National Climate Assessment was released last year, the United States has seen unprecedented flooding in the Midwest, wildfires in Alaska and the Pacific Northwest, heatwaves in the Southeast, red tides in gulf states, extreme cold across the northern parts of the country, the northern spread of vector borne diseases, and abnormally dry conditions across most of the country.

A new report from the Intergovernmental Panel on Climate Change (IPCC) on our oceans and cryosphere confirms that significant changes to our planet from climate change are already underway. These changes range from loss of glaciers, decrease in sea ice, loss of permafrost and a decline in snowfall rates in high mountain areas.

These changes are leading to a variety of problems including biodiversity and habitat loss, sea-level rise, irreversible feedback loops, problems linked to food security and water access, and the elimination of communities that are unable to adapt. While many of the communities that are most vulnerable have the least ability to adapt, even those with significant financial resources will reach technical limitations that limit their ability to adjust to these new realities, if we do not immediately and dramatically reduce greenhouse gas (GHG) emissions.

In short, the more GHG emissions we release, the worse the impacts from climate change will be, and the harder it will be to adapt—no matter where you are.

The Earth’s oceans are being hit hard by climate change

Oceans have absorbed 90% of the excess heat in our climate system, and warming of the oceans has more than doubled since 1993. The oceans are also losing oxygen and absorbing CO₂, making them more acidic. These changes are causing a cascading impact on marine life, weather, and sea-level rise. And loss of marine life will decrease income and food security among marine resource dependent communities.

Ocean warming is increasing the intensity of tropical storms, and coupled with sea-level rise will increase the size of storm surges, leading to more serious damage and loss of life. Changes in ocean currents will lead to more storms in Northern Europe, less summer rainfall in Central Africa, and drive dramatic increases in sea-level rise along the northeast coast of North America, compounding other global warming impacts.

Failure to reduce emissions could drive more emissions

Depending on future emission rates, anywhere between 8% and 89% of permafrost is expected to thaw. We can expect permafrost melting to continue throughout the century and beyond. In the worst-case scenario, this will release tens to hundreds of billions of tons of CO2 and methane into the atmosphere by 2100.

To put this into perspective, human activities released 37.1 billion tons of CO₂ in 2018. Rapid emission reductions will reduce these emissions from permafrost, but depending on the rate of reductions, permafrost emissions may rapidly spiral beyond our ability to control them.

Melting ice is a big deal for everyone

Around 10% of the Earth is covered by glaciers and ice sheets, and these are melting at an alarming rate. Melting ice sheets and loss of glaciers are major drivers of sea-level rise, but they are also increasing the range where some species can live, while pushing other species into extinction.

If we rapidly reduce emissions of greenhouse gases, we can likely hold sea-level rise from melting ice to 2 feet by the end of the century. However, current emission trends could lead to over 16 feet of sea-level rise by 2300. Melting glaciers will increase flooding, mudslides and wildfires, expand the range of these devastating events, and cause negative impacts on food security, water resources, water quality, public health and infrastructure.

It is not too late to stop the worst

No matter what we do in the immediate future, these changes in our oceans and ice cover will continue. But the degree to which they continue, and the extent of these impacts, depend on how quickly we act. This means not only stopping new fossil fuel development and rapidly transitioning to 100% clean renewable energy, but also taking steps to protect those most vulnerable to changes in our climate.