Photo: NASA

Worrying ocean warming levels mark another year record temperatures

It’s official. The year 2020 tied with 2016 as the hottest year on record.  This makes it the sixth consecutive year of exceptionally warm years starting 2015, according to Copernicus Climate Change Service (C3S). The concentration of carbon dioxide in the atmosphere continued to rise in 2020, despite COVID-19 lockdown restrictions, the study also found. A direct result of this has been record high ocean temperatures last year. Scientists have linked warmer oceans to severe storms, floods, droughts and wildfires. The vicious cycle, thus, continues. 

The C3S study revealed 2020 was 0.6°C warmer than the 1981-2010 reference period. But what was more alarming was that the year was 1.25°C warmer than pre-industrial levels, which is eerily close to the 1.5°C target set in the Paris Agreement. The Arctic and northern Siberia, where the wildfire season was unusually active this past year, saw the largest annual temperature deviation – more than 6°C above average.

The study pointed out that while 2020 did match the 2016 record, the former could have easily surpassed the latter’s average temperatures. What prevented this from happening was that 2020 recorded a cooling La Niña event, while 2016 began with a warming El Niño event.

Another recent study found that ocean surface temperatures also reached record high levels last year. The researchers said the hotter temperatures supercharged extreme weather events across the globe.

Oceans have been absorbing more than 90% of the additional heat caused by man-made carbon emissions. A vertical section of the global oceans shows a distribution of the absorbed heat | Source: Cheng et al., 2020

The fact that temperatures on both land and underwater were at their hottest Levels last year cannot be put down to mere coincidence. This is a toxic cycle that has been kick-started by the ever-increasing emission levels. According to scientists, more than 90% of the heat that is trapped by carbon emissions on land is absorbed by the oceans.

Warmer waters feed energy to storms, and push them into the ‘severe’ category. Last year, for example, the Atlantic recorded 29 tropical storms. Another pitfall that warming oceans create is they disrupt rainfall patterns. This, as we saw in Australia, US and southeast Asia, leads to wildfires, floods and droughts. Another consequence, which will be visible by the end of the century, is about a 1m rise in the sea level. This is because seawater expands as a result of the heat. Marine life, which includes underwater ecosystems such as coral reefs, has also been impacted by the repeated ocean heatwaves.

But the most devastating consequence of all is that the warmer the water, the less its ability to absorb the polluting carbon dioxide from the atmosphere. By absorbing the carbon dioxide, oceans work to limit the effect of greenhouse gas emissions on the planet. If this process ends, that would spell doom for the biological systems that govern earth’s natural cycle.

Scientists still believe it is not too late to reverse some of the damage and prevent the inevitable. The past year has given us a glimpse of both ‘what’s to come’ if the inaction continues and ‘what can be’ if the right steps are taken. Now that the Paris Agreement era has begun, the heat is on.

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