Attempts to mitigate global climate change should take into account geographic conditions, says a University of Victoria geographer.
Professor Johan Feddema said, for example, painting roofs white can lower energy use in a hot country where most people have air conditioning. A white roof reflects heat, keeps a structure a cooler and reduces air conditioning demand.
But white roofs in a northern climate are likely to increase energy use. White would reflect the sun in winter, keeping a building cooler and raising the amount of energy needed to heat it. “When we talk about climate solutions, it is site specific,” he said.
Feddema’s research examines and attempts to model how land coverage, forest, grass, desert, rainy or urban conditions affect climate.
He works on attempting to model how changing a land’s cover can alter local climate and how it might contribute to changing global climate patterns.
For example, Feddema can ask what might happen if a forest is removed.
“It doesn’t become a nice sound bite,” said Feddema. “In some places it gets warmer and in some places it gets cooler.”
In northern ecosystems, removing a forest with its insulating effect is likely to have cooling effect, he said. But removing a tropical forest will likely heat things up because less foliage means less evaporation of water and that cooling effect is lost.
A big factor in the human-altered surface of the Earth is an increase in areas with urban environments.
Urban environments tend to be about 2 C warmer than surrounding geographical areas. Brick and concrete absorb heat from the sun during the day and those materials retain heat for hours after dark when the surrounding geographic area cools.
Urban areas usually have less water to cool things down during the day with evaporation. Cities are typically built from surfaces impermeable to water, like asphalt, and engineered with drains to take away rainwater runoff.
Feddema said some solutions to the urban heat effects might lie with changes to building materials. Wood, for example, conducts and holds heat energy less effectively than concrete.
He said the best way to approach the problems of mitigating climate change is to keep the aim simple. For example, reduce emissions of greenhouse gases by saving energy.
“Globally, we want to know what are the best strategies to save energy,” said Feddema. “The reason we want to save energy is to reduce emissions.”
“But with different climates you might want to think about different adaptations to increase or decrease your heat island. That’s the key message. Really think through: ‘What is appropriate for my area?’ ”
