For centuries, humanity has been intoxicated by the idea that it has conquered nature and has absolute control over the changes it makes to it. However, this dangerous myth is definitively refuted by the advent of Anthropocene – a new proposed geological epoch in which our activity not only competes with global geological forces, but has directly torn the Earth system from its safe haven Holocene.

The end of the illusion of control and the crossroads to climate hell

It was the millennia of stable climate conditions of the Holocene that made possible the emergence of agriculture, the flourishing of our cities, and the birth of a socially and technologically complex human civilization. Today, we are abandoning this stable environment with destructive ferocity.

The global average temperature is currently already more than 1°C above pre-industrial levels, bringing us dangerously close to the upper limit of the warm interglacial periods of the last 1.2 million years. Our current trajectory, driven by technological lock-in and socioeconomic inertia, is inevitably pushing us into conditions the planet has not experienced in hundreds of thousands of years. A groundbreaking study by Will Steffen and colleagues (2018) Trajectories of the Earth System in the Anthropocene It confronts humanity with a brutal, straightforward question: Is there a definitive planetary threshold on our trajectory beyond which we lose any chance of controlling our own destiny? If we fail to fundamentally change how we operate in the next two decades, the decisions of our generation will set the planet on an irreversible path to a „greenhouse Earth“ – an inhospitable and uncontrollable world in which modern society has no chance of surviving.

Two different paths: „Greenhouse Earth“ versus „Stabilized Earth“

During the late Quaternary (the last 1.2 million years), the Earth system moved within strictly defined boundaries between glacial and interglacial periods, which essentially formed the so-called limit cycles regulated by changes in the Earth's orbit and tilt. However, in the Anthropocene, we have disrupted this natural cycle. We are witnessing an important crossroads (bifurcation), where two diametrically opposed trajectories open up before us:

1. „"Hothouse Earth": A path driven by internal planetary processes. Once we cross a critical threshold, feedbacks within the Earth system itself will take over and continue to warm, no matter how much humanity reduces its own emissions. The result will be a world with temperatures higher than any interglacial period in the past 1.2 million years and with ocean levels well above the Holocene maximum.
2. „"Stabilized Earth" (Stabilized Earth): An artificially created and managed state in which warming is stabilized at a value up to 2 °C above pre-industrial levels. However, this state is not a natural stable point for the planet – it requires constant and coordinated human stewardship and the purposeful creation of stabilizing feedback loops.

The myth of linearity and the power of biogeophysical feedbacks

Current political discourse suffers from a dangerous notion of linearity. It is assumed that the relationship between emissions and global temperature rise is simple and straightforward: if we reduce emissions by a certain percentage, temperatures will fall or stabilize exactly according to the spreadsheet calculations. However, complex systems analysis refutes this assumption – because biogeophysical feedbacks planets.

While negative feedbacks (carbon absorption by land and oceans) are weakening due to anthropogenic pressure, there is a risk of activation of strong positive feedback. Research shows that with warming of around 2°C by the end of this century, the following additional factors may come into play:

• Permafrost thawing: The release of carbon dioxide and methane from thawing soil will contribute to a further increase in temperature 0.09°C (in the range of 0.04 – 0.16 °C).
• Weakening of physiological absorbents: The decline in the ability of terrestrial vegetation and oceans to sequester carbon (for example, by reducing the efficiency of photosynthesis at high temperatures) will add further 0.25°C (0.13 – 0.37°C).
• Bacterial respiration in the oceans: Increased microbial activity in warmer waters will release more CO₂ and warm the planet by 0.02°C.
• The death of the Amazon rainforest: Converting rainforest to dry savanna will release stored carbon and raise global temperatures by 0.05°C (0.03 – 0.11°C).
• The dying of boreal forests: The retreat of the northern taiga will add to overall warming 0.06°C (0.02 – 0.10°C).

Together, these processes could generate by 2100 additional warming of 0.47 °C (0.24–0.66 °C). Many of these changes are completely irreversible on scales relevant to human society.

Climate Dominoes: A Cascade of Tipping Points

The greatest risk is not posed by these feedback loops in isolation, but by their interconnectedness within the Tipping Cascades. The planet functions like an interconnected domino. Crossing a threshold in one climate element can raise global temperatures enough to trigger a flip in another, more sensitive element.

For example, the melting of the Greenland ice sheet and the loss of Arctic summer sea ice (which are already highly vulnerable to warming of just 1°C to 3°C) will pour huge amounts of freshwater into the North Atlantic. This influx of freshwater could critically disrupt Atlantic Meridian Circulation (AMOC). The slowing of the AMOC will subsequently reduce the northward transport of heat, leading to heat accumulation in the Southern Ocean. This accumulated heat will in turn accelerate basal melting of the ice shelves in West and East Antarctica. Based on these linkages, it is predicted that the definitive planetary threshold may already lie at a warming level of 2.0°C above pre-industrial levels.

Policy failure and the illusion of green growth

The current dominant socioeconomic system is built from the ground up on the principles of high-carbon economic growth and exploitation of natural resources. Political leaders in international forums are ahead of each other in declaring climate goals, but their real actions are paralyzed by the desire to protect national economic interests and maintain the status quo.

Previous efforts to reform this system from within have only brought local successes, but from a global perspective in reducing emissions and protecting the biosphere they failed completely. Politics is stuck in the idea that we will solve the crisis with cosmetic fixes – a modest carbon tax, subsidies for green technologies, or a switch to electric cars – while leaving the core of the economic plunder intact. But the science is clear: Incremental, linear changes to the current socioeconomic system have no chance of keeping the Earth system within safe limits..

Our current management of society, based on theories of gradual development and an emphasis on economic efficiency, is completely inadequate given the nonlinear nature of climate change. The Paris Agreement and its targets (1.5°C to 2°C) are presented as safe limits, but in reality, even successfully reaching this limit carries a serious risk of activating a cascade that will irreversibly tip us onto the path to an uninhabitable planet. Current policies are thus gambling with the very survival of humanity.

What is at stake?

The journey to a "greenhouse Earth" would mean an existential catastrophe for humanity. Our civilization is agriculturally and infrastructurally adapted to the stable world of the Holocene.

• Agricultural collapse: Global agricultural systems are tightly organized around stable Holocene precipitation and temperature patterns. While a Stabilized Earth would allow for partial adaptation, a Hothouse Earth would exceed the limits of our adaptability, leading to a drastic decline in food production, skyrocketing food prices, and deepening global poverty.
• Flooding of megacity: Warming of the Earth system will lead to the flooding of low-lying river deltas and coastal areas, where a significant portion of the world's population lives and critical infrastructure for global trade is located, while coral reefs and their ecosystem services will be completely destroyed by the end of the century.
• Social and geopolitical disintegration: Extreme weather, droughts, and the loss of habitability of entire regions will trigger massive migration waves and threaten the stability of states and global security.

The Need for Systemic Revolution: Before the Door Closes

If we want to maintain the Stabilized Earth trajectory, we must implement rapid and profound transformation of governance, values, behavior and technology. This requires:

• Global decarbonization: Immediate cessation of greenhouse gas emissions.
• Protection and development of natural sinks: Reducing direct human pressure on critical biomes, such as the Amazon and boreal forests, which play a key role in stabilizing the climate.
• Institutional transformation: A fundamental reorientation of national and international institutions towards governance at the Earth system level, with an emphasis on planetary limits in economic governance, trade, investment and finance.
• Building resilience: Since the path to a Stabilized Earth will be turbulent and we will operate in conditions warmer than at any time in the last 800,000 years, we must prioritize building resilience by promoting diversity, modularity, redundancy, polycentric governance systems, and mutual trust in society.

Although there are some signs of societal tipping points—such as slowing population growth through female education and access to family planning—global systemic change is still in its infancy. The door to Stabilized Earth is closing extremely quickly, and time is running out to avert irreversible catastrophe. The decisions we make in the next two decades will determine the fate of our planet for tens to hundreds of thousands of years to come. JRi&CO2AI. Source: PNAS.org