• Compressed source code:gummidi_secerov_climate_change_v1.1.zip
• Seminar presentation : gummidi_secerov_climate_change_v1.2.pdf
• TerraME version: 1.3.0

Climate change is the long-term shift in weather patterns in a specific region or globally. Unlike global warming, which refers to just one aspect of climate change - a rise in the surface temperature of the earth’s surface – climate change refers to changes in a regions overall weather patterns, including precipitation, temperatures, cloud cover, and so on.

According to the scientific experts in the field of climatology, climate change is caused by human activities that have resulted in an increased concentration of greenhouse gases in our atmosphere, including carbon dioxide, water vapor, methane, ozone, and nitrous oxide.

Before the Industrial Revolution, levels of carbon dioxide (the main greenhouse gas) were approximately 280 parts per million (ppm) but have now risen to 386 ppm and are rising by about 2-3 ppm more every year. When combined into what is known as the carbon dioxide equivalent with other greenhouse gases such as methane, current levels are actually around 440 ppm. These levels are higher than any other level that can be accurately measured in the earth’s history. - See more at: http://www.ecolife.com/define/climate-change.html#sthash.I8pdlcUH.dpuf

Our model is trying to show flow of energy, especially heating energy. Energy is coming from the Sun, interacting with the ground and clouds. If it hit the cloud, it can reflect back or transmit through with certain probability. If it hit the ground it can also reflect back or absorb in the ground. After raising the temperature of the Earth, it starts to emit infrared energy. This energy, which is emitted back, can interact with CO2 gases and then it reflects back to the Earth. If it interacts with the cloud, it just pass through. So, in this way we can see model showing global warming. The temperature is raising during the time.

The Earth is represented with pink area. Surface of the Earth is green stripe. Clouds are represented like white squares. Sky is all above the surface of the Earth and it is blue. Sun energy is represented like yellow dots. Energy in the Earth is represented with red dots. Infrared rays have red color. CO2 gases are represented like black squares..

This model can be used, with changing ratios of absorbing, reflection and penetration, for showing speed and trend of Earth's temperature change.

The model has the following steps or interactions:

• The Sun is emitting energy - yellow dots.

• Clouds are white squares and they are moving from left to right.

• CO2 molecules are represented like black squares and they are moving randomly inside the sky.

• The sun rays, i.e. yellow dots, can be reflected from cloud or passing through the cloud, or

• They can hit the Earth and be absorbed or reflected.

• If they are absorbed by the Earth, they turn into red dots. The number of red dots absorbed by the earth has an positive effect on the temperature.

• After some temperature limit, the Earth starts to emit infrared energy, which is represented like magenta dots.

• If infrared rays interact with cloud, they pass through.

• But if they interact with CO2 molecules, energy is reflected back to the Earth, where its absorbed. This is causing temperature rising.

The temperature of the earth is shown on the chart of the model. X axis represents time and Y axis represents temperature.

Assumptions:

1. The Earth has the same albedo throughout without any variations

2. All the clouds has the same albedo throughout

3. The Earth can be heated uniformly and maintains the same temperature all over

After initial running of model, you can try to vary different parameters which model contains.

For example, you can change albedo of clouds and the Earth.

You can add or remove clouds.

You can increase or decrease clouds’ speed.

Also, it is possible to add or remove CO2.

Also, it is possible to specify the concentration (number) of CO2 molecules.

Initial temperature can be set differently.

You can specify the temperature limit when the Earth starts to emit infrared rays.

Speed of rays can be increased or decreased.

So, you can try all this things and try to see how model behaves in different conditions.

You can watch sun ray's path and notice how it interacts with earth surface. Is it absorbed or reflected? You can notice how it interacts with cloud. Is it leaving the sky sometimes?

You can watch infrared ray and notice how it interacts with cloud. Does cloud has any influence on infrared ray? Also, you can watch how infrared ray interacts with CO2 molecules. It is going back, right?

Then, overall, you can compare rising of temperature with increasing of red dots in the Earth (which are heating energy). You can also notice dependance of emitting infrared rays with the Earth temperature.

Play with the model. Try changing different parameters and observe how model will behave.

Try adding more CO2 and see which impact it has on the temperature.

Try changing albedo. Try without CO2 and find albedo when system is in equilibrium.

Try increasing or removing clouds. Which impact does it have?

Run model with different values of parameters and see when it reaches equilibrium.

Try to add the following features to the model:

1. Try to model the clouds in irregular shapes based on different cloud types like Cirras,etc.

2. Try to control the number of clouds in the atmosphere.

3. Try to vary the angle of sunlight and its impact on albedo.

4. Try to add symbols for different features like rays, IRs, CO2 molecules, etc

5. Try to replicate ray behaviour to reflected rays and IRs

You can try to add some other facilities which would extend the model.

For example, you can try to add vegetation. Vegetation has different behavior on absorbing and reflecting energy. It is different comparing with soil and among itself also.

Also, you can try to set different parts of Earth with different albedo. For example, glaciers and water have different values of albedo.

The following TerraMe features are used in the model:

1. CellularSpace

2. Agent

3. Environment

4. Society

5. Timer

6. Legend

7. Observer

and their utilities like forEachCell,? forEachNeighbor,? etc.

“Daisyworld”

Climate Change Model is the parent of “Child of Climate Change” and “Climate Change Lab” models

This model is based on model which can be found at: http://ccl.northwestern.edu/netlogo/models/ClimateChange, created by Uri Wilensky

Model on the address above is based on an earlier version created in 2005 by Robert Tinker for the TELS project.