Could someone give me some advice on how to tackle this question please?
Explain briefly why the changes in albedo and the other factors give rise to the changes in the GMST, relating your explanation to the water cycle. Is this an example of positive or negative feedback?
Thank you
Try reading Book 1!
It really is quite straightforward!
To tackle this question, we first need to understand what is meant by "albedo" and "GMST" and how they relate to the water cycle.
Albedo refers to the measure of the reflectivity of a surface. It indicates how much sunlight is reflected back into space, versus being absorbed by the surface. A higher albedo means more sunlight is reflected, while a lower albedo means more sunlight is absorbed.
GMST stands for Global Mean Surface Temperature, which is the average temperature of the Earth's surface. It is influenced by various factors, including changes in albedo and other factors.
Now, let's consider the role of the water cycle. The water cycle involves the continuous movement of water between the Earth's surface, atmosphere, and back again. It includes processes such as evaporation, condensation, and precipitation.
Changes in albedo and other factors can impact the water cycle, and in turn, affect the GMST. Here's how it works:
1. Changes in albedo: If there are changes in surface reflectivity (albedo), it can impact the amount of energy absorbed or reflected by the Earth's surface. For example, if there is melting of snow and ice in polar regions, it reduces the albedo as darker surfaces (such as rock or water) are exposed. This lower albedo leads to more absorption of solar radiation. As a result, more heat energy is transferred into the Earth's system, increasing the GMST.
2. Other factors: Various factors, such as greenhouse gas emissions, land use changes, or aerosol particles, can also influence the GMST. For instance, greenhouse gases like carbon dioxide trap heat in the atmosphere and contribute to global warming. This causes changes in the water cycle, such as increased evaporation, altering rainfall patterns, and affecting surface temperatures.
In this context, the changes in albedo and other factors affecting the GMST are an example of positive feedback. Positive feedback refers to a process that reinforces or amplifies the initial change. In this case, as the surface temperature increases, it leads to further changes in the water cycle, like increased evaporation, which further amplifies the warming effect. This creates a reinforcing cycle of rising temperatures.
To summarize, the changes in albedo and other factors can impact the GMST through their influence on the water cycle. Changes in albedo, such as reduced reflectivity due to melting snow and ice, lead to more solar radiation absorption, increasing GMST. Other factors, like greenhouse gas emissions, also affect the GMST by altering the water cycle processes. These changes represent an example of positive feedback, as they reinforce and amplify the initial warming effect.