Climate change is the greatest challenge facing humanity. It’s an almighty catastrophe that will only become worse with time. We’ll be seeing more powerful storms, increasingly devastating wildfires, longer droughts and recurring floods, to name but a few of the impacts of climate change that are quickly becoming commonplace globally.

That’s bad enough, but things would be vastly worse were it not for the role played by our oceans and seas. They have been taking a bullet meant for us. Without buffering services provided by the oceans, global warming and other manifestations of climate change would be far worse – for the atmosphere, for terrestrial ecosystems and for societies.

For two centuries the oceans have been mopping up much of the pollution – especially carbon dioxide from the burning of coal and other fossil fuels – that humanity has been dumping into the atmosphere as we have industrialized, developed and grown rich. What’s more, the oceans have absorbed the vast majority of the heat that has resulted from all of that pollution – like an air conditioner in a greenhouse.

However, as we thank our lucky stars that the oceans have mitigated climate change for us, let’s spare a thought for the consequences beneath the waves. In performing global-scale “environmental services” for humanity, the oceans themselves are being severely undermined. Indeed, some of the most profound effects of climate change will occur beneath oceans, across seas and along coastlines.

These effects are already being manifested in rising ocean temperatures. As ocean waters warm and land ice melts, seas are rising and vast areas of our planet are being transformed. What is more, as carbon dioxide pollution from coal plants, factories and cars is absorbed by the oceans, seawater itself is changing: it is becoming more acidic. Marine biodiversity and ecosystems are suffering the effects, in turn creating growing difficulties for communities that depend upon marine ecosystems for sustenance, economic wellbeing and traditional ways of life.

The impacts of climate change on our oceans will bring hardship to people who live, often precariously, along coastlines, and to those who rely on vital resources from the sea. Rising seas are already major threats to some of the world’s poorest countries, most obviously vulnerable small-island countries, some of which face the existential threat of becoming uninhabitable within decades. Other impacts include inundation of cities and other inhabited areas along and near coasts, damage to vital infrastructure, loss of agricultural land, pollution of water supplies and acute devastation wrought by mighty storms.

These and many other adverse climate-related changes to oceans and coastlines cry out for more effective action by governments and other actors. It is vital that the oceans become an integral part of the wider efforts to address climate change, ranging from international agreements to local policies and actions. Effective governance of the oceans can help communities to both mitigate the impacts of future climate change and adapt to its inevitable forces. But doing that will require fully acknowledging the vital role of the oceans and much greater willingness to take far more aggressive action to address climate change.

As we enter 2019, lets pause to give a hearty thanks to the oceans for limiting the impacts of climate change in 2018, and for doing the same in 2019 and beyond. Then let’s make a new year’s resolution to do much more to protect our oceans in the future – because in the real world, the oceans and climate change are inseparable.

Paul G. Harris (www.paulgharris.net) is the Chair Professor of Global and Environmental Studies at the Education University of Hong Kong. He is author and editor of many books on global environmental and climate change politics, policy and ethics, most recently Climate Change and Ocean Governance: Politics and Policy for Threatened Seas (Cambridge University Press, 2019).