Climate System

The Climate System

It is a system that has five key components, the atmosphere, the hydrosphere (this includes the oceans, fresh water, rivers, lakes, and groundwater), the biosphere (living things and soils), the cryosphere (ice sheets, sea ice, and mountain glaciers) and finally the lithosphere (the surface of the Earth's crust).

http://worldoceanreview.com/en/wor-1/climate-system/earth-climate-system/ 
The Water Cycle


Solar radiation causes water to evaporate from the surfaces of the hydrosphere, and also from the biosphere. The water vapour condenses in the atmosphere to form clouds, and water returns to the surface through precipitation. On reaching the surface, water returns to the hydrosphere, it can enter the cryosphere. Sunlight on the cryosphere can melt snow and ice or transform it directly into vapour in a process called 'sublimation' from ice sheets, show fields, and glaciers.

http://www.srh.noaa.gov/jetstream/atmos/hydro.htm 

Human feedback


There are three main feedbacks which are:

• Water vapour feedback 
• Ice Albedo feedback 
• Radiation feedback 

Water vapour feedback


Evaporation occurs when solar radiation heats the surface of bodies of water. The evaporated water is transformed from the liquid to the gas phase and stored in the atmosphere. The molecules of water vapour in the atmosphere absorb heat radiation coming from the Earth below, causing them to vibrate. Then they re-emit heat radiation, some of which comes back down to the surface, resulting in further warming. This increased warming in turn increases the amount of evaporation in an amplifying process, which we call a positive feedback. If we increase temperature, then evaporation increases.

http://www.wsj.com/articles/SB10001424052748704194504575031404275769886
The Ice Albedo feedback


If we take an area of ocean that is mostly covered by sea ice, say in the Arctic, much of the solar radiation that is reaching the surface will be reflected back into the atmosphere by the highly reflective ice. The ocean's surface, on the other hand, will reflect some solar radiation, but it tends to absorb more than it reflects. So if we warm the system up and this melts some sea ice, we'll still have some reflection from the remaining sea ice. But where open water is exposed we'll get much more absorption of incoming sunlight as heat going into the ocean.

http://ossfoundation.us/projects/environment/global-warming/myths/images/arctic/icealbedo.jpg/view
Radiation feedback


All objects give off radiation, but the warmer a body is the more radiation it gives off. And when a warm body gives off more heat radiation, that cools it down. This phenomenon is known as the Stefan Boltzmann effect or the Planck feedback. The Climate system is a system that self-regulates thanks to a mixture of positive and negative feedback. They link together the different components of the climate system.

Weather and Climate

Weather is the state of the atmosphere at a particular point at a specific time which can be described in terms of:

• Temperature
• Precipitation
• Wind speed and direction
• Cloud type and cover
• Humidity
• Visibility

Climate are the average atmospheric conditions of an area measured over a substantial period of time (usually 30 years). This is mainly based on temperature and precipitation.

Koppen classification

There are six broad categories which are:

• Tropical moist climates- all months have an average temperatures above 18 Celsius.
• Dry climates- with deficient precipitation during most of the year.
• Moist mid-latitude- Climates with mild winters (Temperate).
• Moist mid-latitude- Climates with cold winters (continental).
• Polar climates- extremely cold winters and summers.
• Mountain  climates- This category was added later.

http://www.blueplanetbiomes.org/world_biomes.htm

Scientists have to look at how the atmosphere interacts with the oceans, ice sheets, land masses and vegetation. These different interactions create a climate system and these interactions as well as the composition of the atmosphere itself make a very complex system. The sun also drives our climate. Sunlight provides energy which heats the Earth.Without the Earth's atmosphere and certain gases our climate would be very different to what it is now. The atmosphere stops the heat from escaping into space. If it didn't do this our planet would be a very cold place indeed. Certain gases allow the suns energy through but stop it from escaping back into space, acting like a green house. To learn more about the greenhouse effect please read another blog post of mine called 'Blanket Earth'.

Blanket Earth

The main idea for our climate change is the 'Enhanced Greenhouse effect'.

The Greenhouse effect

There is a naturally occurring layer of greenhouse gases in our atmosphere that have made the Earth warm enough for life to flourish.

http://www.livescience.com/37743-greenhouse-effect.html

As the diagram above already explain, people can effect the greenhouse effect. Humans can produce more greenhouse gases which means less infrared radiation escapes to space and therefore warming the Earth too much. Hence the 'Enhanced Greenhouse Effect'. As the Earth warms, the ice caps will melt which will create a rise in sea levels and therefore more flooding.

Greenhouse gases

The natural gases that contribute are: Water vapour, Methane, Carbon dioxide and Nitrous oxide and the only gas that is artificial that contributes are F-gases ( CFCs).
Water vapour is the most abudant greenhouse gas and also it acts as a feedback to the climate. As Water vapour in

creases the Earth warms, as does precipitation creating more Water vapour.

Carbon dioxide is the most important human greenhouse gas which is produced by burning fossil fuels (there has been a rise in CO2 levels since pre-industrial times) and deforestation.

Methane is the second most important greenhouse gas as it is produced by farming (especially cattle and rice), fossil fuel extraction and the decaying of organic waste.

Nitrous oxide is also produced from farming (fertilisers and livestock waste) and industrial processes which also produces F-gases along with refrigeration.

Solar Variability

Its reasonable to assume that the changes in the source's output would be the cause of our climate to change but the amount of energy that the Earth receives from the Sun is relatively stable, however variations occur such as the sunspot cycle ( approximately every 11 years) which result in increased magnetic activity which can be released as solar flares.

A case study that shows a decrease in solar activity is thought to have triggered the Little Ice Age between approximately 1650 and 1850, when Greenland was largely cut off by ice from 1410 to the 1720s and glaciers advanced in the Alps.

If you would like to find out more you can read this article (http://climate.nasa.gov/causes/) by NASA which explains about the contributing gases, the effect that burning fossil fuels has and solar variability.