Why Oceans and Continents Warm at Different Rates: What Explains the Gap

The planet is warming, but certainly not at the same pace everywhere. Why do continents pull ahead of the oceans by such a margin? Behind this striking gap lie two physical properties of water that fundamentally alter the way climate warming manifests itself.

On the warming map, an invisible boundary already separates land and oceans

Viewed from space, warming seems to affect a single planet. Yet, the thermometer tells a far from uniform story. Observations have long shown a faster acceleration on continents. The IPCC estimates that, during certain recent periods, the ratio of terrestrial to ocean warming hovers around 1.6.

The year 2025 again reminded us how important this dynamic is. Copernicus ranked this year as the third warmest on record globally, behind 2024 and, by a hair, 2023. The last eleven years now form the eleven warmest on record in the available datasets.

The ocean holds a vast thermal reservoir that land is deprived of

The first explanation can almost be boiled down to a pot of water. It takes a lot of energy to raise water temperature, far more than warming a dry soil. This strong thermal capacity turns the oceans into a colossal climate buffer, capable of absorbing immense energy without their surface temperature rising as swiftly.

And “immense” is no exaggeration. According to NOAA, the ocean absorbs about 91% of the excess heat accumulated in the climate system due to greenhouse gases. Ocean currents churn this energy and transport it to the depths, where it spreads across vast volumes of water.

However, this apparent slowdown conceals a trap. An ocean that heats slowly does not escape warming. Its thermal content continues to rise, fueling the expansion of water and intensifying marine heatwaves. In 2025, the oceans stored a record amount of heat, confirming this underlying trend.

When water evaporates, it carries away a precious portion of the heat

The ocean has another advantage, almost akin to natural air conditioning: evaporation. When its surface receives more energy, a portion goes into turning liquid water into vapor rather than directly raising surface temperature. This process consumes energy and thus limits surface warming of the sea.

On land, the mechanism quickly hits its limits. A humid forest or a water-saturated soil can also evaporate and transpire, but when reserves diminish, this cooling wanes. More energy then drives the sensible heat, the kind that truly pushes the thermometer up and intensifies heat episodes.

This physical lag ultimately reshapes human summers in very tangible ways

Here is where physics leaves the climate graphs. The bulk of humanity lives on land, precisely where warming amplifies the most. Higher average temperatures favor more intense heatwaves and increase soil evaporation, with direct consequences for farming, water resources, and urban areas.

The phenomenon can even become locally self-perpetuating. When soil dries out, it evaporates less water and returns more energy to the air as heat. This soil–heat feedback loop then strengthens certain heatwaves. A few weeks without rain can sometimes create conditions conducive to extreme temperatures.

Thus, oceans are not a “cold” part of climate change. They form the vast heat reservoir of the Earth system, while continents reveal its effects in the air that populations breathe more rapidly. The essential question remains: how can our landscapes be adapted to a world where the land continues to warm faster than the global average?