Weather determines our existence - how much rainfall, lngth of the growing season, amount of sunlight, length of the winter, depth of the snowpack. All of it. Even frequency of hurricanes and snowstorms affect where and how we can live.
There are so many ways to answer this question that I can only hope you are ready to sift through the many paths posed. I would say that weather can impact earth through crop production and basic sustenance. Farmers all over the world are dependent on the natural conditions of climate and weather to ensure bountiful harvests and the generating of profit. Another way weather impacts earth is through mere rainfall. Some areas of the earth might have to endure periods of weather where there is too much rainfall and others, not enough. Enduring this could be another example of how weather affects Earth. The generation of tropical storms and hurricanes is another way in which weather impacts Earth. Hurricans like Katrina and Andrew demonstrated the profound effect weather can have on people and their lives.
Weather affects the inhabitants of Earth more than it affects the planet itself. Whole civilizations have sprung up and died because of the effects of the weather over the millenia.
Seventy-three percent of the Earth's surface is covered by water, and that water is continually moving through what is commonly called "The Water Cycle". This cycle is what fuels our weather and determines the various climates and biomes of the planet. It determines where, how, and why people live where they do. It determines their mode of dress, what type of house they live in, the food they eat, and even the length of their life span.
Without water, man cannot survive. Our creator has given us our marvelous weather system to not only provide life-giving water to us all, but to remind us of His goodness and matchless power. Even atheists will have to admit of the grandeur and awesome power of the forces that have shaped our plant, made it what it is, and that continue to shape it in the future!
This is such a big question that it is practically impossible to answer. Perhaps you can look at this answer and then ask a more specific question...
In a sense, weather does not affect the Earth as a planet. The Earth continues to orbit the Sun and spin on its axis regardless of what kind of weather is happening.
Weather does, of course, affect various landforms on the Earth. Blowing wind can shape rocks by erosion. Storms can change the shape of coastlines. In this way, weather can change the shape of landforms.
More importantly, weather affects the biosphere -- the environment that allows life to exist. Changes in the weather can have an impact on what plants and animals can survive in a given place, for example.
Perhaps you can write an answer of your own here and clarify your question...
Weather occurs due to density differences between one place and another. These differences can occur due to the sun angle at any particular spot, which varies by latitude from the tropics. The strong temperature contrast between polar and tropical air gives rise to the jet stream. Weather systems in the mid-latitudes, such as extra tropical cyclones, are caused by instabilities of the jet stream flow. Because the earth's axis is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. On earth, common weather phenomena include wind, cloud, rain, snow, fog and dust storms. Less common events include natural disasters such as tornadoes, hurricanes, typhoons and ice storms.
Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes due to differences in compressional heating. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location.
For example, the green lung of the planet is affected by global warming.
Trees remove more carbon dioxide than in the past. Because of global warming, trees and other plants from the northern hemisphere, came to remove carbon dioxide in the atmosphere, rather than absorb it.
Normally, the carbon dioxide produced by human activities is absorbed by plants and oceans, are then released back into the atmosphere through the process of decomposition. A study published in the journal Nature, shows that worldwide, winter starts later, and spring starts earlier.
Also, in the northern extremes,temperatures during spring and autumn have increased about one degree Celsius. This means a longer growing season for plants, a phenomenon that scientists believed beneficial to the atmosphere. Study results have shown the opposite because plant debris tend to get in decomposition process earlier than normal,generating large quantities of carbon dioxide in the atmosphere.