Even though this finding has been present in climate literature for years, it still manages to surprise people when put simply: the land is warming more quickly than the ocean, and in the tropics, the difference is becoming concerning. Not even slightly quicker. Not a little more concerning. In some areas, where billions of people cultivate food, gather water, and live near the ground, land surfaces are warming at a rate that is about twice that of the ocean under the same sky.
Even though it took decades to fully develop the explanation, physics is not difficult once it is explained. Water protects the climate system from the harm caused by rising temperatures. Warmth is absorbed and dispersed over vast depths by oceans. They cycle, evaporate, and cool. Land is incapable of doing any of that. When the land is dry, as it is in much of the tropical belt, it heats up quickly because there is no moisture to evaporate and remove the excess energy. There is no way for a dry surface to cool itself under a warming sky. It just gets hotter.
For years, Dr. Michael Byrne of the University of St Andrews developed a quantitative theory for precisely this. It turns out that the obvious solution—that land has a lower heat capacity than water—is only partially accurate. The lapse rate—the rate at which temperature decreases as altitude increases—is the more basic driver. As the climate warms, this rate falls more precipitously over oceans, which contain more water vapor. Surface temperatures on dry land must rise more quickly and forcefully than those over water due to this difference in atmospheric behavior. Although Byrne himself has pointed out that this finding hasn’t yet fully reached the general public, it has been well received in climate dynamics circles. which is problematic in light of the current real-world numbers.
Key Facts: Tropical Warming & the Land-Ocean Heat Divide
| Topic | Accelerated warming in tropical land regions vs. ocean surfaces |
| Key Research Institution | University of St Andrews / University of Oxford |
| Lead Researcher | Dr. Michael Byrne, earth surface processes lecturer |
| Key Finding | Tropical land heats nearly twice as fast as oceans during elevated CO₂ periods |
| Asia Warming Rate | Nearly twice the global average (WMO, 2025 data) |
| Ocean Heat Record | 2025 ocean heat content: highest since records began in 1960 |
| Ocean Heat Rise (2025) | ~23 zettajoules — equivalent to ~40 years of global primary energy use |
| Primary Driver | Atmospheric lapse rate dynamics + land dryness, not just heat capacity |
| WMO Warning Issued | March 23, 2026 (World Meteorological Day) |
| Regions Most Affected | Southeast Asia, Sahel, Central Asia, Arabian Sea, tropical Atlantic |
| Reference Links | Why Land Warms Faster Than Oceans – Carbon Brief · Rising Temperatures Hit Asia Hard – WMO |
The best example of where this is going is Asia. Asia is currently warming at a rate that is almost twice that of the rest of the world, according to the World Meteorological Organization’s State of the Climate in Asia report. Asia’s average temperature in 2024 was roughly 1.04 degrees Celsius higher than the baseline from 1991 to 2020, and the warming trend between 1991 and 2024 was nearly twice as high as it had been between 1961 and 1990. There is no stabilization of the numbers. They are speeding up. The region’s sea surface temperatures rose at a rate of about 0.24 degrees per decade, which is twice the average rate of ocean warming worldwide. Marine heatwaves of strong, severe, or extreme intensity affected nearly 15 million square kilometers of Asian ocean surface in 2024; this area was more than 1.5 times the size of China and larger than the Russian Federation.
All of this has a cascade of effects that resemble a list that someone put together to make a point, but each item is current and documented. The strongest storm of 2024, Tropical Cyclone Yagi, devastated China, Vietnam, the Philippines, Laos, Thailand, and Myanmar. Over 100,000 people were forced to flee Kazakhstan after record rainfall caused the worst flooding the area had seen in at least 70 years. Over 350 people were killed by landslides in northern Kerala, India, following a 48-hour period of intense rainfall that totaled over 500 millimeters. At least 246 people were killed and nearly $94 million worth of damage was caused by floods in Nepal in September. In contrast, a drought in China cost hundreds of millions of dollars, destroyed hundreds of thousands of hectares of crops, and impacted 4.8 million people. Some areas are being soaked by the same warming, while others are being desiccated.
The ocean is attempting to mitigate all of this by absorbing over 91% of the planet’s excess heat, but even this buffering comes at a cost. In 2025, the ocean’s heat content hit its highest point since records started in 1960. Over the last 20 years, the rate of ocean warming has more than doubled from 1960 to 2005. Ocean heat increased by about 23 zettajoules in 2025 alone, according to a global team of more than fifty scientists. This is roughly equal to four decades’ worth of primary energy consumption absorbed in one year. Even during La Niña conditions, which are usually accompanied by some surface cooling, about 90% of the ocean’s surface saw at least one marine heatwave in 2025. Even in their off-years, the oceans are heating up.
As all of this is happening, it seems like the discussion about climate change has been a little out of place for a while, concentrating on global averages when the most drastic changes are profoundly regional, profoundly physical, and disproportionately affecting the areas least able to withstand them. The tropics are not geographical abstractions. Over three billion people live there. They are where a large portion of the world’s food is produced, where harvests are determined by monsoons, and where coastal fishing communities rely on seas that are frequently too hot for the ecosystems they once supported. coral bleaching on a large scale. Fish species are either declining or changing their range. The Himalayan glaciers, which provide hundreds of millions of people with freshwater, are losing mass at rates not seen since measurements started.
How all of this is resolved in the upcoming decades is still up in the air. Because it is still technically challenging to accurately simulate how dry land is today, a crucial variable in Byrne’s theory, climate models differ significantly in their regional projections. The land warms more when it is drier.
Additionally, the land is becoming drier in a significant portion of the tropical belt. This produces a feedback loop that is difficult to accurately model but easy to comprehend in terms of direction. Drying is accelerated by the warming. Warming is intensified by the drying. The people who live there are the ones who notice the difference—not in parts per million of atmospheric carbon, but in harvest failures, dry wells, and rooftops submerged under two meters of floodwater.
