Beneath our feet, Earth has a conveyor belt of hot, molten rock that constantly churns, carrying heat from the planet's core to the surface. This process, known as mantle convection, is driven by the difference in temperature between the Earth's hot interior and its cooler exterior.

However, a new study has revealed that a stiff layer of rock deep within the Earth's mantle is disrupting this conveyor belt. The layer, which is located about 930 miles (1,500 kilometers) beneath the surface, is preventing the hot rock from rising from the core, causing it to accumulate and form a bulge.

This bulge is disrupting the flow of the mantle convection currents, which is causing the Earth's surface to heat up. The study, published in the journal Nature, suggests that this could be the cause of the recent increase in global temperatures.

The researchers believe that the stiff layer of rock is the result of a change in the composition of the mantle. This change could be due to the addition of water from the Earth's surface or from the melting of ice from the polar ice caps.

The findings of this study have important implications for our understanding of how the Earth's climate works. They also suggest that we need to better understand the processes that occur deep within the Earth's mantle if we want to accurately predict how the planet's climate will change in the future.