Scientists have described three scenarios for Earth's future before the year 3000

Scientists have described three possible paths the Earth's climate could take before the year 3000.

The work is published in the journal Earth's Future.

Its authors consider the future of the Anthropocene - the time when human activity became one of the main forces changing the planet. The term "Anthropocene" itself is not approved as an official geological epoch, but it is widely used in Earth system science.

The main message of the study is simple: the future is not yet set, but the longer emissions continue, the harder it will be to keep the climate within relatively safe limits. Even small residual emissions, such as from agriculture or land use, can have a large effect over time.

Details

The authors of the paper looked not just at the next few decades, but over a very long period - up to the year 3000. This is important because the climate is changing slowly. Carbon dioxide can stay in the atmosphere for a very long time, oceans continue to store heat, and melted glaciers don't recover in a few years.

Scientists have described three scenarios.

The first scenario is the most manageable. In it, mankind quickly reduces emissions, stops increasing warming and gradually begins to remove some carbon dioxide from the atmosphere. In this scenario, temperatures may peak around mid-century and then decline very slowly. This does not mean an instant return to the climate of the past, but the risks remain more manageable.

The second scenario is the dangerous one. In it, emissions decline too slowly. Warming increases and then sticks at a higher level for a long time. The planet then does not necessarily go into the worst case scenario, but people will have to live in a world with more frequent heatwaves, changes in precipitation, and pressures on agriculture, cities and health.

The third scenario is the most worrisome. It involves not only human emissions, but also the response of nature itself. If the warming becomes too strong, feedbacks could intensify: permafrost would release more greenhouse gases, forests would absorb less carbon, Arctic sea ice would reflect less sunlight. Then some of the processes may start to support warming themselves.

Simply put, we are talking about "climate inertia". Even if a person hits the brake, the huge system will not stop immediately. That's why the authors use the image of the "quicksand of the Anthropocene": the deeper humanity goes into warming, the harder it is to get out without active action.

At the same time, the study does not say that "all is already lost". On the contrary, the authors emphasise: there is still a choice. Every year and every tonne of emissions matters because they determine how hot and unstable the future will be.

Why it matters

This work is important because it shifts the focus from the familiar question of "what will happen by 2100" to the longer horizon. For climate, 2100 is not the end of history. The consequences of today's decisions can persist for centuries and even millennia.

It's especially important to realise this when talking about net-zero emissions. Net-zero, or "net zero," means that humanity emits no more greenhouse gases than it can remove or offset. But it's not an "undo warming" button. Once this balance is reached, the climate may stabilise, but many of the effects - such as ocean warming or rising sea levels - will persist for a very long time. The IPCC also points out that some of the changes in the ocean, ice sheets and sea level are irreversible on scales of centuries and millennia.

The practical conclusion is simple: the earlier emissions are cut, the better the chance of keeping the climate in a manageable state. The longer action is delayed, the greater the risk that humanity will have to deal not only with its own emissions, but also with the consequences of natural processes already set in motion.

Background

The Anthropocene is a term used to describe an era of strong human influence on the Earth. Humans changed the composition of the atmosphere, climate, water cycle, forests, oceans, soils and biodiversity. Geologists have not formally established the Anthropocene as a new epoch, but in climatology and Earth science, the word helps describe the extent of human influence.

In the past, climate projections were more often discussed within the 21st century: how much warmer it will get by 2050 or 2100. But that's a short time frame for the planet. The ocean can store extra heat for centuries, ice sheets react slowly, and the carbon cycle doesn't return to its previous state immediately.

A new study clarifies this picture: it shows that the big question is not just how much the Earth will warm in the coming decades, but whether a long entrenchment in a hotter state can be avoided.

Source

Study: Johan Rockström and co-authors, "We Are in the Anthropocene-Now What?", Earth's Future magazine, 2026.