The oceans are getting warmer every year – here’s why you should care about it

• Oceans have long taken the brunt of the impacts of human-made global warming, according to a report by UN Climate Change.
• The oceans are home to almost 80% of all animal life, says a recent Statista report, which are deeply affected by climate change.
• Here is why oceans getting warmer is worrisome.

The world's oceans grew to their warmest and most acidic levels on record in 2021, according to a study by World Meteorological Organisation (WMO) released earlier this month. The report provides more evidence that Earth is warming at an accelerated pace.

It is a record that keeps getting broken year after year. And this could have a major impact on the Earth’s climate.

How can oceans influence Earth’s temperature?

Oceans and atmosphere work hand-in-hand to form and regulate Earth’s climate.

Earth absorbs radiation and energy from the sun, and converts some of it into thermal energy or heat. Earth’s surface, which includes both land and oceans, absorbs heat from the sun. What isn’t absorbed, is reflected back into the atmosphere.

Oceans cover 70% of the Earth’s surface, which is why they absorb the largest amount of heat. The heat capacity of water is 4.186 Joules/gram °C, which means that the ocean water can absorb four times more solar radiation than air before its temperature will rise by one degree.

The bodies of water absorb around 90% of the Earth's accumulated heat. So, our oceans play a major role in keeping the Earth cool because of its massive capacity to absorb heat.

The oceans also produces 50% of the planet’s oxygen and absorb around 30% of carbon dioxide produced by humans, buffering the impacts of global warming. The oceans, therefore, act like the lungs of Earth.

Increasing CO2 causes ocean acidification; puts lives at risk

Increasing carbon dioxide (CO2) and other greenhouse gas (GHG) emissions from human activities are making oceans more acidic, which has put marine species and ecosystems at risk.

As the amount of carbon dioxide in the atmosphere increases, a chemical reaction occurs between carbon dioxide (CO2) and ocean water (H2O). This chemical reaction creates harmful carbonic acid (H2CO3).

On the 14-point pH scale, ocean pH has been at around a slightly basic 8.2 for the past 300 million years. The acidity of a liquid is reported as pH. The lower the pH value, the higher the acidity of a liquid.

Prior to the industrial revolution, average ocean pH was about 8.2. Today, average ocean pH is about 8.1.

A pH drop of 0.1 might not seem like much of a difference. However, each decrease of pH unit is a ten-fold increase in acidity. This means that the acidity of the ocean today, on average, is about 25% greater than it was during pre-industrial times.


So, the oceans bear the effects of warming, acidification, among other processes, creating many existential threats to nature, communities and livelihoods around the world.

“Sea level rise, ocean heat and acidification will continue for hundreds of years unless means to remove carbon from the atmosphere are invented. Some glaciers have reached the point of no-return, and this will have long-term repercussions in a world, in which more than 2 billion people already experience water stress," said WMO Secretary-General Professor Petteri Taalas.

Oceans are home to a majority of animal life

Oceans are home to almost 80% of all animal life, fish alone making up one third of all animal biomass. As per a report by analytics firm Statista, the world is home to an estimated number of 8.8 million species with around 1.7 million of them already being identified and described.

One of the most vulnerable ecosystems is warm water coral reefs, which are already dying off as a result of climate change. An increase of 1.5 °C in global temperature will cause 70– 90% of the warm water coral reefs that exist today to disappear. Losses will be up to 99% in the case of warming of 2 °C or more.

Why is increasing ocean heat worrisome?

The ocean has warmed markedly faster in the last 20 years, hitting a new high in 2021, and is expected to become even warmer, a recent WMO report said. That change would likely take centuries or millennia to reverse.

Ocean warming is leading to the melting of inland glaciers and ice, causing rising sea levels.

This rising level further causes coastal erosion, flooding, habitat loss, saltwater contamination of freshwater sources and affects coastal human settlements.

The long-term trend below shows that the top 700 meters of the oceans have become warmer since 1955. Particularly warmer sea surface temperature provides energy for storms and thereby triggers extreme weather events.

The oceans are our Earth’s lungs and it is important to keep them healthy to keep the Earth’s temperature in check.