Afforestation is always thought of as a positive change in the environment around us as it sequesters carbon from the atmosphere, thereby mitigating climate change significantly. However, the biophysical effects – land surface albedo, evapotranspiration and cloud cover – of afforestation are often not taken into account. I will incorporate these into a simplistic climate model that will help me quantify these effects and interpret them accordingly.
I am thinking about using a three part climate model to study the effects of afforestation and deforestation on global mean temperatures. I will be taking three latitudes in approximation. They are as follows:
- Equatorial: 0-30 degrees
- Mid Latitudes: 30-60 degrees
- Polar Regions: 60-90 degrees
Albedo: It is surface reflectivity and is a dimensionless quantity. “0” albedo means the surface is a perfect absorber (black) and “1” would mean a perfect reflector (white).
Albedos for different surfaces:
- Ocean: 0.06
- Sea Ice: 0.5 – 0.7
- Snow: 0.9
- Deciduous Trees: 0.15 to 0.18
- Coniferous Trees: 0.09 to 0.15
- Grasslands: 0.25
- Desert Sand: 0.40
- Tundra: 0.20
The Earth’s planetary albedo is approximately 30 – 35 %. This can vary for different areas due to cloud cover, vegetation and other factors influencing the environment of that region.
The next step is to create a simple model that will study the net changes when we use different variables i.e. albedo values for each of the regions.
Evapotranspiration has to be incorporated into the model — still working on how to do that.
It is also possible that transpiration could be negligible in some areas and therefore we could ignore it. Also, water vapors can travel from one region to another and we need to account for that.
Depending on the results from above, cloud cover may or may not be incorporated into the model.
The carbon cycle is a biogeochemical process by which carbon is exchanged among the biosphere, pedosphere, hydrosphere and the atmosphere of the earth.
The global carbon budget is the balance of the exchanges of carbon between the carbon reservoirs or between one specific loop of the carbon cycle. Examination of the carbon budget of an area can tell us whether it is a sink or a source of CO2.
Carbon is an important part of the atmosphere around us and unwanted changes in its quantity in the atmosphere can cause disastrous effects. To combat global warming – which is being caused by releasing large amounts of CO2 into the atmosphere – countries, agencies and individuals around the world are propagating afforestation, reforestation and other relevant ideas, mechanisms and projects.
However, afforestation projects around the world have, rather surprisingly, shown both positive and negative results. Often, we fail to consider other factors when we talk about carbon sequestration. For example, planting trees on a piece of land can change the Albedo or the surface reflectivity of the land. Darker areas have lower albedo which means that more absorption takes place. This would lead to warming of the earth, meaning, afforestation can potentially cause an increase in the global mean temperature of the earth. A major implication of this is that the positive results of carbon sequestration projects are often neutralized by other phenomenon such as changes in albedo.
This calls for an in-depth examination of the nature of plants being considered for afforestation and the land being used to avoid unwanted and unforeseen results. Dendrometry, which is a branch of tree allometry, studies the dimensions of trees using parameters such as:
- Diameter at breast height.
- The height of the tree.
- Horizontal dimension of the canopy.
It is interesting to note that the above parameters are influential while defining a forest. Different countries have different definitions of forests and these could be evaluated keeping in mind the above parameters and factors that influence the environment around us.
I would be interested in examining and studying in detail the above – rather controversial – research project through this semester.
Interesting article that I found during my research on the topic: Climate Effects of Afforestation: Carbon sequestration and changes in land surface albedo.
The Lower Olentangy Urban Arboretum project sounds very interesting to me. I have been fascinated by the Arboretum on campus and feel that it would be a good idea to study the kind of plants that a campus like OWU would like to have. Some could be planted just because they look nice, some could be due to their high carbon sequestration potential, some could be due to the effects they have on the soil and some could be planted for fruits! Maybe we could have an orchard on campus to supply fruits to OWU students in the future!
I am also interested in studying different plants in different latitudes of the world and how they affect livelihoods of people in that region. Maybe I could do a cost-benefit study of how the geography of a particular area affects its people in social and economic terms.
I have also been always fascinated by the El Nino current and the diverse effects it has on the oceanography of different regions. It also affects the environment of the region and hence the people living there. I would be interested in studying this in detail under the project.