 There are a couple of other processes that also enable the transfer of energy from the sun and another one is the latent heat of evaporation. Now I guess we can think about this one as being part of the process that drives the water cycle, we sometimes call it the hydrologic cycle, and what happens is energy from the sun evaporates water from the surface, so from lakes and dams and rivers and ponds but of course from the ocean and the energy that it takes to evaporate that water allows this massive transfer of energy to the earth and that's called the latent heat of evaporation. And so that's another mechanism for getting energy into the earth system and as I said it drives the hydrologic cycle so most of you are probably familiar with this, you have the evaporation, then condensation to form the clouds and ultimately precipitation so what happens is there's a sink of energy to cause the evaporation which is stored as potential energy in the clouds and then when it rains we release that energy again so once it's in the earth system it tends to be a bit more of a closed system in these cycles not entirely but more typically.