The causes of climate change
Natural causes
Anthropogenic causes
The solar irradiance is the output of light energy from the entire disk of the Sun, measured at the Earth, which is the main contributor of energy to Earth. When incoming energy from the sun is absorbed by the Earth system, Earth warms.
Changes in solar output might affect our climate—both directly, by changing the rate of solar heating of the Earth and atmosphere, and indirectly, by changing cloud forming process.
Earth reflectivity, as know as albedo is the amount of solar radiation reflected from Earth, often expressed as a percentage. Earth as a whole has an albedo of about 30%, meaning that 70% of the sunlight that reaches the planet is absorbed.
Earth reflectivity avoids the climate from being too hot or cold, which depends on Earth’s surface and atmosphere. Light-colored objects and surfaces, like snow and clouds, tend to reflect most sunlight, while darker objects and surfaces, like the ocean, forests, or soil, tend to absorb more sunlight.
Earth's energy balance
Energy balance describes how the incoming energy from the solar irradiation is used and reflected to space by the Earth. If incoming and outgoing energy are in balance, the earth's temperature remains constant.
The hydrological cycle of the earth is the sum total of all processes in which water moves from the land and ocean surface to the atmosphere and back in form of precipitation.
The process of water cycle
Earth’s water content:
96.5% global ocean
1.7% polar icecaps, glaciers, and permanent snow
1.7% groundwater, lakes, rivers, streams, and soil
1% water vapor
Evaporation: Warmth from the sun irradiance causes water from oceans, lakes, streams, ice and soils to rise into the air and turn into water vapor.
Evaporation absorbs lots of solar irradiance, thus cools down the temperature.
Condensation: Water vapour in the air cools down and turns back into liquid water.
Precipitation: Water (in the form of rain, snow, hail or sleet) falls from clouds.
Collection: water that falls from the clouds as rain, snow, hail or sleet, collects in the oceans, rivers, lakes, streams. Most will soak into the ground as underground water.
The greenhouse effect is a process that occurs when gases in Earth's atmosphere trap the Sun's heat. This process makes Earth much warmer than it would be without an atmosphere. The greenhouse effect is one of the things that makes Earth a comfortable place to live. 
The process of greenhouse effect
In the daytime, Sun shines through the Earth's atmosphere to warm the surface.
At night, the surface cools down while some of the heat is trapped by the gases in the atmosphere.
The heat-trapped gases are called greenhouse gases
Water vapor
Carbon dioxide
Methane
Water vapor is the most abundant greenhouse gas and also the most important in terms of its contribution to the natural greenhouse effect.
Changes in reflectivity affect how much energy enters Earth’s climate system.
A large greenhouse effect can raise the temperature of the Earth's surface, thus acclerates the water cycle process by quickening the evaporation first, which will bring about more flood and drought.
Burn fossil fuels
Humans—more specifically, the greenhouse gas (GHG) emissions we generate—are the leading cause of the earth’s rapidly changing climate.
Deforestation
Worsen greenhouse effect by adding excess greenhouse gases into the atmoshpere..
Since the industrial revolution around 1750, human activities have added significant quantities of greenhouse gases into the atmosphere.
Activities like agriculture and road construction can change the reflectivity of the earth’s surface, leading to local warming or cooling, too.
Transportation emission
Agriculture and livestock
Road construction
Greenhouse gases and aerosols affect climate by altering incoming solar radiation and outgoing infrared (thermal) radiation that are part of Earth’s energy
balance.