The Earth's energy imbalance has doubled, and it's a cause for concern. This isn't just about heatwaves; it's about the planet's overall health and the future of our climate. Here's why this matters, and what it means for all of us.
The Heat is On
The Earth's energy imbalance, the difference between the amount of energy entering and leaving the planet, has doubled in recent decades. This is a record-breaking increase, and it's a clear sign of human-caused climate change. The Earth is accumulating heat faster than ever before, and the consequences are far-reaching.
Where the Heat Goes
Most of this excess heat doesn't stay in the atmosphere. It's absorbed by the oceans, which act as a vast heat sink. But this isn't without consequence. The oceans are warming, ice sheets and glaciers are melting, and permafrost is thawing. Sea levels are rising too, driven by thermal expansion and melting ice.
The rate of sea level rise is speeding up. Between 1901 and 2018, it rose by around 1.7mm per year. In the past decade, this rate has more than doubled to over 3.6mm per year. This might not sound dramatic, but even small increases can have big impacts.
Marine Heatwaves and El Niño
Marine heatwaves are now around three times more frequent than they were in the early 1990s. In 2025, an average area in the ocean would have experienced about 65 marine heatwave days, which is nearly one day in five. This is a substantial increase, and it's a clear sign of the energy imbalance's impact.
On top of this, the energy imbalance combines with natural climate patterns like El Niño. While El Niño events are natural, today's are happening in a world that already has a warmer baseline. This means that the impacts of El Niño are more severe, and they can lead to drought, heavy rainfall, and flooding.
The Future is Uncertain
The prospect of a strong El Niño in the very near future is a stark reminder of how natural variations and human-caused warming can combine to produce intense impacts. But it's the steady, continuous build-up of heat that will shape the decades ahead.
The key point is that as long as more heat enters the Earth system than leaves it, temperatures will continue to rise. Until we bring the planet back into balance by drastically reducing greenhouse gas emissions and reaching net zero, that heat will keep building. And as it does, the extremes we're experiencing now will only become more frequent, more intense, and harder to manage.
In 2025, human-caused global warming reached about 1.37°C above pre-industrial levels, and we're edging closer to the 1.5°C threshold. At the current pace, that limit could be crossed in around four years. This is a critical moment, and it's time for urgent action to address the energy imbalance and its impacts.
