What causes convection currents inside earth

Differential heating and pressure.

Convection currents occur when lighter (or not as dense) warm materials rise over cooler, more dense, and heavier material sinks below it. These movements occur inside the mantle, or the third from inner-most layer of the Earth, and are often the cause of tectonic plate moment.

a warm, wet climate will produce the highest rate of weathering. the warmer a climate is, the more types of vegetation it will have and the greater the rate of biological weathering (figure below). this happens because plants and bacteria grow and multiply faster in warmer temperatures.