Climate and weather are a result of the physics and chemistry of the atmosphere and its interactions with the landforms and oceans of Earth. Over the centuries people have gathered a wealth of information about climate and weather but there is a much that is not yet understood. Climate is the overall picture of weather during periods of seasons or years. In recent historical times human activities such agriculture, development of cities, use of technology, and changing of landscapes has been causing additional climate change. The growing of crops to feed the populations of the world, is directly affected by climate change.
Food production is totally dependent on favorable growing conditions.
Extensive droughts, for example, can result in deaths from starvation and can cause serious economic problems when the hungry populations migrate to more fortunate regions. Weather is the air temperature, cloud cover, precipitation, and wind at any particular time in any particular place. Weather reflects the prevailing conditions of the air masses overlying the land and seas over the entire globe. Weather patterns over a period of time present a picture of climate. The entire atmosphere surrounding Earth is in constant motion caused by the uneven heating effect of the sun due to the spin of the Earth on its axis as it orbits the Sun.