Land Cover and Climate Change
Production of greenhouse gasses is only one way humans are changing the environment. A KU researcher is examining how land cover - agricultural fields, urban concrete, and suburban development - alters local climate.
Aired June 2, 2008
2 minutes (2.5 MB) | Download mp3
Research shows that changes in land cover influence the Earth's climate. From the University of Kansas, this is Research Matters. I'm Brendan Lynch.
Humankind's manufacture of greenhouse gasses is the main engine of climate change. But Johannes Feddema, KU professor of Geography, says we also impact our climate by covering land with crops, urban concrete and suburban sprawl.
Johannes Feddema: "As humans change a landscape, chop down a forest and replace it with bare ground or cotton or something else, it will change the reflectivity of the surface and that changes the amount of energy that is absorbed, and then ultimately energy that's available to evaporate water, to conduct into the ground, to be used for photosynthesis. It changes the path of energy through the environment. And ultimately the temperature of an object is just the reflection of its energy content."
Feddema says that while we think of climate change as a process affecting all parts of the Earth equally, altering land cover actually brings on local climate changes.
Feddema: "The same human impact - deforestation - can lead to warming in one area of the earth and cooling in another. We talk about global warming. Carbon dioxide and greenhouse gasses are fairly evenly spread around the planet, and we sort of see this response that's similar everywhere, whereas the response to land cover tends to be what we call offsetting - we might cool bit here and warm things there - so its not nearly as easy to get that nice sound bite where you say, 'Look, this is the effect,' because it varies from region to region."
Although cities cover just two percent of Earth's surface, Feddema says cities are where many people experience climate, in what he calls urban heat islands.
Feddema: "Fifty percent of our population lives in urban centers. If we were to ask, 'What's the influence of climate on that urban population?' Well, there's the global climate that we might talk about , but the reality is that they're living in an urban environment that has a completely different climate. You have small sort of 'hot spots.' You could create plumes over urban areas. Not only do you get an urban heat island, but there is some impact on precipitation downwind."
For more on land cover and climate change, log onto Research Matters dot K-U dot E-D-U. For the University of Kansas, I'm Brendan Lynch.
Tell Me More
Professor Johannes Feddema
My primary research focuses on the study of natural and human induced climate change, and the impacts of these changes on human and environmental systems. I developed this interest early in life, growing up on three continents and seeing the impacts of climate and environmental degradation first hand in vastly different communities.