Earth Is Trapping More Heat Than Ever — And Low Climate Sensitivity Models May Be Wrong

Written By Ingrid Lung

Why satellite data is rewriting the rules of climate prediction — and raising the stakes for global action.

The Planet’s Energy Imbalance Is Growing — and That’s a Big Deal

For years, climate scientists have debated how much Earth will warm as carbon dioxide levels climb. The answer depends in large part on a measure called climate sensitivity — the amount of long-term warming expected if CO₂ levels double. A new peer-reviewed study published in Science has now delivered a major reality check: models that predict lower sensitivity may be underestimating Earth’s response to greenhouse gases.

The paper, authored by Gunnar Myhre and colleagues, uses over two decades of satellite observations to show that Earth’s energy imbalance is not just real — it’s accelerating. In simple terms, our planet is absorbing more solar energy than it is releasing back into space. This imbalance is the engine of global warming, and its observed strength over the past two decades casts serious doubt on models that predict only modest temperature rises.

What Is Earth’s Energy Imbalance — and Why Does It Matter?

Every second, Earth receives energy from the sun. Some of this energy is reflected back into space, and the rest is absorbed, warming the planet. Earth then emits heat (infrared radiation) back out. The difference between incoming and outgoing energy is known as Earth’s energy imbalance (EEI).

The study analyzed data from NASA’s CERES satellite instruments between 2001 and 2023. What it found is striking:

  • There has been a clear increase in incoming solar radiation, mainly due to fewer reflective clouds.

  • At the same time, outgoing longwave radiation has not increased as much, because the Earth’s surface — and particularly the oceans — has been absorbing more heat.

This means the planet is storing energy at an accelerating rate, with serious implications for ice melt, sea level rise, extreme weather, and future climate scenarios.

Climate Models Under Scrutiny: Why Low Sensitivity Isn’t Holding Up

Climate models are the bedrock of policy planning, helping us understand how emissions today will shape the world tomorrow. But not all models are created equal.

Some models estimate that a doubling of atmospheric CO₂ would lead to a relatively modest warming of around 1.5 – 2.5°C. Others suggest much higher warming, exceeding 3 – 4.5°C. These variations come down to how each model simulates cloud feedbacks, ocean heat uptake, and aerosol effects — all complex processes.

Here’s where the new study delivers a seismic shift:

  • Low-sensitivity models fail to reproduce the observed energy imbalance trends.

  • In particular, they underestimate the rise in shortwave (solar) radiation being absorbed, and they misrepresent cloud-related warming feedbacks.

  • The study concludes that only models with a climate sensitivity above ~2.5 – 2.9°C are consistent with the satellite record.

This finding suggests that the planet is likely to warm more — and faster — than many governments and industries are currently planning for.

What This Means for Climate Policy and the Global Carbon Budget

If low-sensitivity models are indeed too optimistic, the window for avoiding dangerous warming narrows significantly. The Paris Agreement aims to keep global temperature rise well below 2°C, ideally 1.5°C. But a higher climate sensitivity means:

  • The remaining carbon budget is smaller than thought.

  • More aggressive emissions cuts are needed to stay within safe limits.

  • Current national targets (NDCs) may fall far short of what’s required.

In other words, the time for half-measures is over. This study reinforces the need for rapid decarbonization, large-scale renewable deployment, and investment in climate resilience.

Clouds, Climate, and Uncertainty: A Call for Better Models

A major reason for the discrepancy lies in how clouds are modeled. Cloud cover can either cool the planet (by reflecting sunlight) or warm it (by trapping heat). Subtle changes in cloud dynamics — especially in the tropics — can amplify or dampen global warming.

The satellite data reveals that fewer reflective clouds are forming, particularly over the oceans, which allows more solar energy to reach Earth’s surface. This positive cloud feedback is not fully captured in some older or lower-sensitivity models.

Improving how we model clouds and aerosol interactions is now a scientific priority — one that could reshape projections for decades to come.

The Bottom Line: We’re Running Out of Time, and Excuses

This groundbreaking research sends a clear and urgent message:
The Earth is responding more strongly to carbon pollution than some climate models have suggested. That’s not just a scientific detail — it’s a wake-up call for every policymaker, investor, business leader, and citizen on the planet.

Higher climate sensitivity means more warming, faster, and with less room for error. The choices we make in the next few years will define not just the next decades, but the future of life on Earth.

Sources and Further Reading

Ingrid Lung
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