Global urban areas may rise above 4℃ by 2100
Science and Technology Daily (Reporter Zhang Mengran) British "Nature·Climate Change" magazine recently published a climate science research in which scientists used statistical models to predict the complex "urban climate" of the 21st century.
The results show that under the high-emission climate change scenario, the global urban areas may rise by more than 4°C by 2100, and the humidity will also be relatively reduced.
More than half of the world's population lives in cities.
The high population density and high-intensity economic activities will consume a lot of fuel and release countless gases and dusts. These, together with other human production and life activities, have changed the original regional climate conditions in the area, forming a different kind from the surrounding cities. Local "urban climate".
The temperature rise in cities is generally greater than in rural or suburban areas, because various concrete and asphalt surfaces will absorb more heat and hinder cooling. It can be said that many buildings in cities constitute a special kind of "ground."
Incorporating these variables into climate change predictions is essential for understanding the future "urban climate", but it is not easy for researchers to actually operate them.
Researchers at the University of Illinois in the United States have constructed a statistical model that combines climate modeling with data-driven methods to provide multi-model predictions of the global "urban climate" in the 21st century.
This model can simulate the complex climate in urban areas, and the research team subsequently applied this "urban climate simulator" to global climate models for 26 medium and high emission scenarios.
This process can transform the rough climate model results into city-level temperature and relative humidity predictions, thereby quantifying climate change and uncertainty.
The research team estimates that by the end of this century, global cities will have an average temperature increase of 1.9°C under the medium emission scenario and 4.4°C under the high emission scenario, and the consistency between climate models is good.
They also predict that the relative humidity of the city will drop almost entirely, which will make surface evaporation more efficient, and it also means that adaptation strategies such as urban vegetation may be effective.
The researchers said that these results will be made public, hoping to help city planners and decision makers predict the changes in specific cities throughout the 21st century.