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Sounds like a broken record: why climate change keeps outdoing itself

El Niño conditions and small particles in the air are two factors likely to blame for stifling heat and warming oceans
This article was originally published on The Conversation.

In the past few weeks, climate records have shattered across the globe. July 4 was the hottest global average day on record, breaking the new record set the previous day. Average sea surface temperatures have been the highest ever recorded and Antarctic sea ice extent the lowest on record.

Also on July 4, the World Meteorological Organization declared El Niño had begun, “setting the stage for a likely surge in global temperatures and disruptive weather and climate patterns.”

So what’s going on with the climate, and why are we seeing all these records tumbling at once?

Against the backdrop of global warming, El Niño conditions have an additive effect, pushing temperatures to record highs. This has combined with a reduction in aerosols, which are small particles that can deflect incoming solar radiation. So these two factors are most likely to blame for the record-breaking heat, in the atmosphere and in the oceans.

El Niño’s big comeback

The extreme warming we are witnessing is in large part due to the El Niño now occurring, which comes on top of the warming trend caused by humans emitting greenhouse gases.

El Niño is declared when the sea surface temperature in large parts of the tropical Pacific Ocean warms significantly. These warmer-than-average temperatures at the surface of the ocean contribute to above-average temperatures over land.

The last strong El Niño was in 2016, but we have released 240 billion tonnes of CO2 into the atmosphere since then.

El Niño doesn’t create extra heat but redistributes the existing heat from the ocean to the atmosphere.

The ocean is massive. Water covers 70 per cent of the planet and is able to store vast amounts of heat due to its high specific heat capacity. This is why your hot water bottle stays warm longer than your wheat pack. And, why 90 per cent of the excess heat from global warming has been absorbed by the ocean.

Ocean currents circulate heat between the Earth’s surface, where we live, and the deep ocean. During an El Niño, the trade winds over the Pacific Ocean weaken, and the upwelling of cold water along the Pacific coast of South America is reduced. This leads to warming of the upper layers of the ocean.

Higher than usual ocean temperatures along the equator were recorded in the first 400 metres of the Pacific Ocean throughout June 2023. Since cold water is more dense than warm water, this layer of warm water prevents colder ocean waters from penetrating to the surface. Warm ocean waters over the Pacific also lead to increased thunderstorms, which further release more heat into the atmosphere via a process called latent heating.

This means that the build up of heat from global warming that had been hiding in the ocean during the past La Niña years is now rising to the surface and demolishing records in its wake.

Small particles in the air help and hinder climate change mitigation efforts

Another factor likely contributing to the unusual warmth is a reduction in aerosols.

Aerosols are small particles that can deflect incoming solar radiation. Pumping aerosols into the stratosphere is one of the potential geoengineering methods that humanity could invoke to lessen the impacts of global warming. Although stopping greenhouse gas emissions would be much better.

But the absence of aerosols can also increase temperatures. A 2008 study concluded that 35 per cent of year-to-year sea surface temperature changes over the Atlantic Ocean in Northern Hemisphere summer could be explained by changes in Saharan dust.

Saharan dust levels over the Atlantic Ocean have been unusually low lately.

On a similar note, new international regulations of sulphur particles in shipping fuels were introduced in 2020, leading to a global reduction in sulphur dioxide emissions (and aerosols) over the ocean. But the long-term benefits of reducing shipping emissions far outweighs the relatively small warming effect.

This combination of factors is why global average surface temperature records are tumbling.

It’s not too late

In May this year, the World Meteorological Organization declared a 66 per cent chance of global average temperatures temporarily exceeding 1.5 C above pre-industrial levels within the next five years.

This prediction reflected the developing El Niño. That probability is likely higher now, since El Niño has developed.

Within the next five years, there is a 66 per cent chance of global average temperatures temporarily exceeding 1.5 C. Photo: Louis Bockner / The Narwhal

It is worth noting that temporarily exceeding 1.5 C does not mean we have reached 1.5 C by the Intergovernmental Panel on Climate Change standards. The latter describes a sustained average global temperature anomaly of 1.5 C, rather than a single year, and is likely to occur in the 2030s.

This temporary exceedance of 1.5 C will give us an unfortunate preview of what our planet will be like in the coming decades. Although, younger generations may find themselves dreaming of a balmy 1.5 C given current greenhouse emissions policies put us on track for 2.7 C warming by the end of the century.

So we are not at the point of no return. But the window of time to avert dangerous climate change is rapidly shrinking, and the only way to avert it is by severing our reliance on fossil fuels.

Like a kid in a candy store
When those boxes of heavily redacted documents start to pile in, reporters at The Narwhal waste no time in looking for kernels of news that matter the most. Just ask our Prairies reporter Drew Anderson, who gleefully scanned through freedom of information files like a kid in a candy store, leading to pretty damning revelations in Alberta this spring. Long story short: the government wasn’t being forthright when it claimed its pause on new renewable energy projects wasn’t political. Just like that, our small team was again leading the charge on a pretty big story

In an oil-rich province like Alberta, that kind of reporting is crucial. But look at our investigative work on the Coastal GasLink pipeline to the west, or our Greenbelt reporting out in Ontario. They all highlight one thing: those with power over our shared natural world don’t want you to know how — or why — they call the shots. And we try to disrupt that.

Our journalism is powered by people just like you. We never take corporate ad dollars, or put this public-interest information behind a paywall. Here’s the thing: we need 300 new members to join this month to meet our budget. Will you join the pod of Narwhals that make a difference by helping us uncover some of the most important stories of our time?
We’ve got big plans for 2024
When those boxes of heavily redacted documents start to pile in, reporters at The Narwhal waste no time in looking for kernels of news that matter the most. Just ask our Prairies reporter Drew Anderson, who gleefully scanned through freedom of information files like a kid in a candy store, leading to pretty damning revelations in Alberta this spring. Long story short: the government wasn’t being forthright when it claimed its pause on new renewable energy projects wasn’t political. Just like that, our small team was again leading the charge on a pretty big story

In an oil-rich province like Alberta, that kind of reporting is crucial. But look at our investigative work on the Coastal GasLink pipeline to the west, or our Greenbelt reporting out in Ontario. They all highlight one thing: those with power over our shared natural world don’t want you to know how — or why — they call the shots. And we try to disrupt that.

Our journalism is powered by people just like you. We never take corporate ad dollars, or put this public-interest information behind a paywall. Here’s the thing: we need 300 new members to join this month to meet our budget. Will you join the pod of Narwhals that make a difference by helping us uncover some of the most important stories of our time?

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The Narwhal’s reporters uncover energy stories that send shockwaves throughout Canada. But they can’t do it alone — we need to add 300 new members this month to meet our budget. Will you support crucial climate reporting that makes an impact?