This is how climate change is impacting the ocean - and what we can do about it

The ocean is inextricably linked to our climate. Rising air temperatures due to global warming are melting the polar ice caps and dissolving glaciers, leading to rising sea levels.

But the ocean is also playing a crucial role in protecting us from the worst effects of climate change. Scientists say the seas have absorbed 90% of all the warming that has taken place in the past 50 years.

On the rise

The Intergovernmental Panel on Climate Change (IPCC) says that by 2100, sea levels will be between 0.26 metre and 0.77 metres higher than today. It’s estimated that by 2100, rising sea levels will threaten 200 million people who live in low-lying coastal areas.

Researchers say that almost half of the world’s sandy beaches could disappear as sea levels rise. It’s estimated that by 2050, more than 570 cities will be affected by a sea level rise of 0.5 metres.

Warming seas

The IPCC also estimates that even if the rise in global air temperatures can be held to 1.5°C, sea temperatures will rise by at least 2 °C by the end of the century.

Rising sea temperatures are to blame for “coral bleaching”. When the water is too warm the corals expel the algae living in their tissues and turn white. Scientists say that coral can recover from bleaching events but it is permanently weakened.

Our changing waters

Meanwhile, melting freshwater from the world’s polar ice sheets changes the chemical composition of the sea making it hard for some species to survive. A study of the Baltic Sea warned that reducing salinity could threaten zooplankton, the tiny creatures who represent the foundation of the marine food chain.

Freshwater also changes ocean currents and if these fail or change course it can lead to oxygen-depleted “dead zones” where marine animals and plants cannot survive.

The oceans are our biggest carbon sink, absorbing around one-third of the CO2 emitted by human activity since the start of the Industrial Revolution.

Adding CO2 to seawater in these quantities acidifies the oceans and this is affecting many marine species, especially clams, mussels and sea snails which are unable to grow their shells in acidified waters.

Coral research is making waves

Conservationists and community groups are taking action to restore their coral reefs. In Jamaica, which lost 85% of its coral to hurricanes and pollution, “coral gardeners” are nurturing young corals.

There’s hope, even, for the Great Barrier Reef in Australia, where scientists have developed a process they call “coral IVF” in which they collect coral sperm and eggs and grow new young corals which are then implanted in areas that have been bleached. They say the results are promising.

Meanwhile, corals in the Red Sea have been found to keep their colour, showing resistance to higher temperatures. Scientists conducting a genetic analysis on coral samples in the Gulf of Aqaba found those corals, and the algae and bacteria they live in symbiosis with, can withstand average temperatures 5°C higher than what they typically experience. It means they can identify 'super coral' that can withstand heat stress.

Towards sustainability

The carbon sequestration that the ocean provides will be vital if we are to slow the rate of global warming, says the International Union for Conservation of Nature (IUCN) which has called for 30% of the ocean to be designated as Marine Protected Areas (MPAs) by 2030.

Fishing and tourism needs to become more sustainable and coastal development needs to be controlled to prevent marine environments being harmed, says the IUCN. It adds tht research must continue so new measures can be developed as the damage to our seas becomes more obvious.

Power to regenerate

The World Economic Forum has convened the Friends of Ocean Action, a group of 65 global leaders from business, civil society, international organizations, science and technology committed to fast-tracking solutions to the damage caused to our seas by climate change.

“We have the knowledge, power and technology to put the ocean on a path to recovery,” says the Friends’ mission statement. “The ocean’s power of regeneration is remarkable, if we just offer it the chance.”

Meanwhile, on 25-26 May, the Forum’s Virtual Ocean Dialogues event aims to encourage practical dialogue on the global ocean action agenda.

The Forum’s Uplink innovation crowdsourcing platform is also bringing environmental entrepreneurs together to share their innovations to save and protect the ocean, ranging from zero-carbon shipping to the restoration of coral reefs.