For many, the great big blue may seem like a mysterious expanse. But everyone, everywhere is greatly impacted by the state of the sea, whether aware of it or not. On World Oceans Day, we recognize that the world’s largest carbon sink has suffered greatly at the hands of human industrialisation – particularly extractive practices such as the fossil fuel industry.

The oceans and their inhabitants absorb about a quarter of the carbon dioxide we release into the atmosphere. Coral reefs buffer shorelines from the effects of hurricanes. Offshore wind farms and tidal energy provide potential renewable alternatives to dirty fossil fuels. Coastal cultures worldwide are influenced and shaped by relationships with the ocean. The livelihoods of 10-12 percent of the world’s population – that’s over 870 million people – depend on fisheries and aquaculture.

All of this is at stake if we do not make a just transition away from fossil fuels and towards renewable energy. Here’s why:

1. The ocean is heating up

The ocean absorbs vast quantities of heat as a result of increased concentrations of carbon emissions in the atmosphere, mainly from fossil fuel consumption. We have just finished the hottest May on record, and this increasingly popular trend of record temperatures causes coral bleaching and the loss of breeding grounds for marine fishes and mammals. Ocean warming leads to deoxygenation – a reduction in the amount of oxygen dissolved in the ocean – and sea-level rise – resulting from the thermal expansion of sea water and continental ice melting. 

2. Coral reefs are particularly under threat

About 70-90% of all existing coral reefs are expected to disappear in the next 20 years due to warming oceans, acidic water and pollution. About 500 million people earn their livelihoods from the fishing stocks and tourism opportunities reefs provide, and all of this is at risk because of increased ocean acidification. The ramifications of a warming ocean are many, and acidification is a particular threat to some of the most biodiverse parts of the planet. Scientists are trying to save coral reefs with innovative practices, but this is only a temporary fix. All six major coral reef extinctions in the geological past have been due to excessive warming and acidification, and if we are to avoid future bleaching events, we need to rid the planet of the effects of fossil fuels.

3. Less ice in Arctic equals more spread of disease

Rising carbon emissions and temperatures aren’t only a threat to tropical oceans. The alarming rate of melting ice opens the door for a wider spread of contaminants and diseases. We have learnt from the current COVID pandemic that the climate crises exacerbates all forms of health emergencies. If we do not try our best to achieve the targets set by the Paris Agreement on climate change and hold the increase in the global average temperature to 1.5°C, the climate crises could very well place us and marine animals at risk of another health emergency.

4. Oil spills

A massive deepwater oil spill is nearly as likely today as it was in 2010. Just this month, Russia declared a state of emergency in northern Siberia after more than 20,000 tons of diesel fuel spilled into a river near the Arctic Ocean. Millions of gallons of oil are released into the oceans each year from a number of sources, including natural seeps, drilling, and spills from ships and pipelines.


These are just a few of the many devastating effects that the climate crisis – and the fossil fuel industry – have on the world’s oceans. This year’s theme for World Oceans Day is “Innovation for a Sustainable Ocean” and now, more than ever, the world’s leaders must be innovative in ensuring a just transition away from fossil fuels and toward 100% renewable energy. The solutions are within our grasp, and for the future of this great blue planet and humanity, we must grab them.