Earth is a giant heat engine, and its thermostat is currently running a fever.

Nature · Published 3 October 2026 Swipe more like this →

In short: Earth functions as a massive, solar-powered heat engine, constantly balancing incoming sunlight with outgoing thermal radiation. While this delicate equilibrium has kept our climate stable for millennia, human activity is now trapping extra energy, causing a measurable imbalance that is fundamentally altering the planet's temperature and weather patterns.

At the top of our atmosphere, Earth receives an average of 340 watts of solar power per square meter. Because the planet is a sphere, this energy is not distributed evenly; the tropics receive a surplus, while the poles face a deficit. To prevent the equator from overheating and the poles from freezing, the atmosphere and oceans act as a global heat engine, circulating energy through winds, ocean currents, evaporation, and rainfall to redistribute heat toward the poles.

This system relies on radiative equilibrium: the balance between incoming solar energy and the heat Earth radiates back into space as infrared radiation. However, this balance is fragile. Factors like clouds, aerosols, and surface albedo—the reflectivity of surfaces like ice or dark forests—constantly influence how much energy is absorbed or reflected. When the amount of energy entering the system exceeds what escapes, the planet must warm up to restore balance.

Recent data from NASA’s CERES instruments and other research show that this equilibrium is currently disrupted. Greenhouse gases are preventing infrared radiation from escaping, leading to an accumulation of energy. Estimates indicate that the global energy imbalance has risen from under 0.60 watts per square meter at the end of the 20th century to 0.79 watts per square meter between 2006 and 2018. This trapped energy is driving rapid changes, such as the loss of Arctic sea ice and variations in global weather patterns, as the Earth system works to accommodate the surplus.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Why Earth’s surface is nearly 60 degrees Fahrenheit warmer than the sun alone allows
• Why Earth’s climate system is a complex web of self-reinforcing and balancing loops
• Why the Earth is heating up: the delicate physics of incoming and outgoing energy
• Earth stays cool by shedding invisible heat into the vastness of space
• A tiny shift in temperature masks a massive surge in planetary heat
• The Earth is warming, and the consequences are already reshaping our global landscape.
• From cosmic nebulae to your living room, dust is the universe's quiet architect.
• Climate change is already reshaping the global food system, from production to your plate.
• Why the lightest rain might be the most powerful force in our climate
• Climate change is not just an environmental crisis but a direct threat to human health.
• How truck-mounted radar revolutionized our understanding of the most violent storms on Earth
• The world's oceans are absorbing the brunt of human-driven climate change impacts

More in Air · More in Nature · Latest · A–Z · All topics