A catastrophic event took place on Earth about 12,000 years ago. At that time, the Earth was just coming out of its last ice age. An increasing amount of solar radiation was pouring into the northern hemisphere and atmospheric greenhouse gases were rapidly increasing. Huge ice sheets that had grown over North America and Scandinavia during the preceding 100,000 years were receding rapidly, raising global sea level by hundreds of metres.

Then, all of a sudden, Europe was plunged back into an ice age. In the course of two to three decades temperatures plummeted, sea ice expanded, and mountain glaciers started to grow again. The frigid conditions would persist for another 1300 years before warming resumed and the Earth fully emerged from the ice age.

This event was first discovered by scientists looking at lake sediments. They found the fossil remains of an Arctic flower, Dryas Octopela, but over time discoveries made by scientists examining marine fossils from deep ocean sediments helped us better understand what likely took place.

The main cause of this abrupt climate event was the Earth getting warmer. How can that be? How can warming trigger a return to an ice-age climate?

The ocean is key

Seventy-one percent of the planet is covered by ocean, so the ocean is key to regulating our climate. Disrupt the ocean and you disrupt the climate.

That is because major currents in the ocean move heat around the Earth. Warm water on the surface flows from the tropics to the north, where it cools, giving off heat to Europe, and then sinks to form a deep-water cold current. The warm current is connected to the cold current like a big conveyor belt. This conveyor belt system is how heat is transported around the Earth.

When the Earth was warming 15,000 years ago, freshwater was pouring off the land from melting ice sheets and glaciers and into the ocean — right where the deep cold current forms. Remember, the saltier the water, the heavier. So the freshwater pouring in made the water too light to sink and shut down the conveyor belt, stopping the heat transport system. This meant heat from the tropics was no longer being moved north and a return to ice age climate.

After another 1000 years or so the circulation began again and we fully emerged from the ice age to the Holocene conditions of today. These are the conditions in which civilisation developed, in which countless cultures have been created. These are the conditions in which humans cultivated plants and animals for food and power.

But the relatively stable climate and ecosystems of the past 10,000 years are gone. Year after year more and more oil and gas is being dug up and burnt, trapping more and more heat, fueling a torrent of extreme weather events. And once again, as the Earth warms rapidly, ice sheets are melting and freshwater is pouring into the North Atlantic.

Scientists say there are already signs that the ocean’s conveyor belt is slowing. New research suggests the ocean conveyor belt could be shut down, like it was in the past, within the next few decades.

This would not plunge us into an ice age. The conditions are different this time. But it would have catastrophic consequences for everybody on Earth. Europe would become cooler, but the tropics and the whole of the southern hemisphere would get hotter. The areas where it is too hot to live and work would expand.

It would also shift the major rain belts and affect the monsoons. That means, the most important impact on us, would be on our food system.

Our global food system

Over the past 50 years, agribusiness and big food corporations have moulded our food system: from what we eat — increasingly “The Global Standard Diet” whereby wheat, rice, corn and soy account for almost 60% of the calories grown by farmers — to how people access and even think about their food.

This means that locally, we have more diverse food, but globally, we do not. Crucially, it means our food system is extremely vulnerable to shocks.

George Monbiot writes in his recent book, Regenesis: “The Global Standard Diet creates the Global Standard Farm. These farms are not only at risk of harvest failures. They are also monoculture dead zones for wildlife. Agriculture is the biggest driver of wildlife population declines and species extinction, better known as the biodiversity crisis.”

That is because firstly their expansion has meant deforestation and destruction of ecosystems. But also year after year they use huge amounts of inputs — fertilisers and pesticides — that destroy the soil ecosystem, pollute our rivers and lakes, and create massive dead zones in coastal waters. These farms are also highly irrigated and are powered and fed by fossil fuels.

Despite the promoted image of the small family farm, the vast majority of farms — more than 70% — are owned or controlled by just 1% of “farmers”, which include investment banks, pension funds, hedge funds and private-equity vehicles. Of course these farmers are not and never have been interested in producing nutritious food. They are interested in producing profits.

Rise of the far right

In the face of these compounding risks — of abrupt climate change and major disruptions to our food system — what has been the response of capital and governments?

After decades of dragging their feet, they accept the science of climate change and biodiversity loss. But their solution, of course, is the market. We must tax ordinary people. Charge them for driving their cars. Tell them to stop using straws and paper cups. Recycle more. They must change, not the big oil companies who are burning our future, nor the big tech companies building data centre after data centre, driving up energy needs.

And for the actual small farmers who already face extreme weather events and reduced crop yields, who already don’t make enough to get by, they have to change, not the big meat processing plants and grocery store giants that set the prices.

This approach to climate and biodiversity action, which says ordinary people’s lives must radically change, that you must change your life, while the system causing the crisis — capitalism — is maintained, has fueled a new climate denialism and pushed a section of people towards far-right and fascist parties.

In the recent European elections, the far right finished first in France, Italy and Austria and came second in Germany and the Netherlands. In Ireland, the far right got into local councils for the first time and a right populist candidate gained a European seat for the first time.

All of this — the risk of climate tipping points, of species extinction, of more violence, death and destruction, of the rise of the far right and fascism, of pushing back women’s rights and gains for the LGBTQ+ community — will continue as long as this system is in place. Capitalism cannot get us out because capitalism equals barbarism.

We, and our life support systems are being sacrificed on the altar of profits for the very very wealthy, not us. We do not benefit.

What is to be done?

Strategically, we need to place an understanding of the ecological crisis at the centre of what we are doing. We are not just ecosocialists when we are campaigning about the environment and socialists the rest of the time.

We are ecosocialists when we are trade unionists and housing activists. Within the trade union movement, we are the people saying that the ecological crisis is a workers’ issue and we need to be involved. Within the environmental movement, we are the ones pointing to the power of the organised working class and the need for system change to be ecosocialist change.

Programmatically, we need to reject any promotion of growth as the answer to the crises that the majority of people on Earth face. Instead, we have to recognise that to sustain a livable future for humanity and a just transition for all — workers, small farmers and Indigenous peoples in the Global South and advanced capitalist countries — it is necessary to reduce the total consumption of energy and raw materials.

That is for two reasons. First, to quicken the transition to 100% renewable energy. Second, to avoid further breaches of the other planetary boundaries. We cannot allow more and more extraction of minerals — such as copper, cobalt and lithium from the Global South — to make more and more cars for rich countries, devastating nearby environments and communities.

That means degrowth to zero energy use on the military and advertising. It means drastic reductions in the consumption of the super-rich, with bans of private jets and yachts. This would allow growth in energy use for people in the Global South within planetary boundaries.

It means advocating for a good life for every person on the planet. That does not mean a superabundance of material private goods. Instead, we want high-quality public goods, the decommodification of the commons and all aspects of life, and the healing of the rift between humanity and nature. We want an emphasis on being rather than having.

We want mass retrofitting of people’s homes to reduce energy consumption and investment in green jobs including so-called care jobs (childcare, education and healthcare). We want free, green and frequent public transport getting people out of private cars. We want universal basic services, a ban on planned obsolescence and enshrining a right-to-repair of all consumer goods.

We want an agricultural model ensuring the right to a decent income for all farmers while shifting away from high energy-intensive beef and dairy farming to low-energy regenerative farming. We want a four-day week without loss of pay. And crucially, we want a democratically planned economy so that we can collectively choose what to spend our energy and resources on.

Ecosocialism or barbarism

At the beginning of World War I, when revolutionary socialist Rosa Luxemburg was campaigning against the war, she declared: “Today, we face the choice — either the triumph of imperialism and the collapse of all civilization as in ancient Rome, depopulation, desolation, degeneration — a great cemetery. Or the victory of socialism, that means the conscious active struggle of the international working class against imperialism and its method of war.”

Today, more than 100 years later, the choice is the same: ecosocialism — a socialism that centres the ecological crises — or barbarism. 

We have a choice. The climate has changed, but every 10th of a degree matters. Every ecosystem matters and, of course, every human life matters. We do not have to accept this rotten system, which threatens everything we hold dear.

We have to build the “conscious active struggle of the international working class against imperialism” to stop the destruction and save as much as we can. 

But we should not just build a defence. We must also go on the offense and build a movement not just to tear down this system, but to build another world — an ecosocialist world.


This article is based on Jess Spear’s presentation to Ecosocialism 2024. Spear is an ecosocialist activist and local organiser for People Before Profit based in Dublin, Ireland. Originally from the United States, she worked as a climate scientist for the United States Geological Survey before becoming a full-time socialist organiser. She is co-founder of the revolutionary Marxist group RISE and was chief editor of Rupture magazine