Featured Research

from universities, journals, and other organizations

Worsening Urban Air Pollution Won't Increase Global Temperature Over Next 100 Years

Date:
September 20, 2000
Source:
American Geophysical Union
Summary:
Researchers using a new climate change model predict that urban air pollution will increase significantly over the next 100 years, but although it may affect regional temperatures, globally it will not have a significant effect on surface temperature.

WASHINGTON - Researchers at the Massachusetts Institute of Technology have found that although urban air pollution is expected to increase significantly in the coming century, it will not have a big effect on global temperature change.

Related Articles


While there may be temperature increases in certain regions, global mean surface temperature will not go up significantly because of urban air pollution, researchers at MIT's Joint Program on the Science and Policy of Global Change wrote in a paper to be published in the September 27 issue of the Journal of Geophysical Research--Atmospheres.

Using a method that allows global coupled-chemistry climate models to take urban air pollution into account in a new way, MIT researchers found that compared to a reference run excluding urban air pollution, the average tropospheric ozone concentration decreases while high concentrations of ozone are projected in the urban areas. As a consequence of the change in the chemical composition of the troposphere, the lifetime of methane increases. This leads to higher ambient methane concentrations, even if emissions are unaltered. As ozone decreases and methane increases, the net effect on the radiative budget of the Earth is small, because the contributions from these two greenhouse gases partially cancel each other out.

"People thought things would go in this direction, but they couldn't quantify it before," said Monika Mayer, research scientist at MIT's Department of Earth and Atmospheric Sciences and lead author on the paper, "Linking local air pollution to global chemistry and climate."

Global climate models are used by researchers to predict future conditions and to aid global policy matters such as the Kyoto Protocol. One example is the MIT Integrated Global System Model, which includes an economic development model; a two-dimensional land and ocean resolving interactive chemistry-climate model that divides the planet into 24 latitudinal bands; a terrestrial ecosystems model, and a natural emissions model.

While scientists agree that urban air pollution can alter concentrations of greenhouse gases such as ozone in the troposphere, they have left the complicated chemistry of urban air pollution out of global climate models. "Global-scale models that do not take into account urban areas' highly nonlinear atmospheric chemistry most likely overestimate tropospheric ozone production due to unreasonably high background nitric oxide concentrations," the authors write.

Yet, "high-resolution climate models don't have chemistry coupled to them," said Dr. Mayer. "It takes months just to run a global climate model without the chemistry."

Dr. Mayer and her colleagues, Chien Wang, Mort Webster, and Ronald G. Prinn, applied a method that allowed them to derive a computationally efficient urban air chemistry model from a state-of-the-art urban airshed model. They then coupled the "reduced form" urban air pollution model to the MIT integrated global climate model. This makes the global chemistry-climate model more powerful and comprehensive, because it is able to take urban air pollution into account in a way never before possible. "Our model takes about one day on a conventional workstation for a 100-year simulation. This is a powerful way to get interactions among air pollution, methane and other tropospheric gases," Dr. Mayer said.

Among the questions the more powerful model may help answer: How do air pollution and climate policies interact? What are the long-term effects of regional regulations regarding air pollution? What are the long-term effects or cost savings of targeting only greenhouse gases or more stringent Environmental Protection Agency air pollution regulations?

Population projections show that in the next 100 years, the concentration of people in urban areas will increase dramatically. While 30-40 percent of air pollution currently comes from urban areas, as much as 70 percent may originate from cities in the future. The researchers carried out three simulations of 100-year projections that factored in the effects of increased urban air pollution tied to population increases and economic development in these areas. They found that even with significant increases in air pollution, global mean temperature should not change much, although there may be more pronounced regional effects.

###


Story Source:

The above story is based on materials provided by American Geophysical Union. Note: Materials may be edited for content and length.


Cite This Page:

American Geophysical Union. "Worsening Urban Air Pollution Won't Increase Global Temperature Over Next 100 Years." ScienceDaily. ScienceDaily, 20 September 2000. <www.sciencedaily.com/releases/2000/09/000919114525.htm>.
American Geophysical Union. (2000, September 20). Worsening Urban Air Pollution Won't Increase Global Temperature Over Next 100 Years. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2000/09/000919114525.htm
American Geophysical Union. "Worsening Urban Air Pollution Won't Increase Global Temperature Over Next 100 Years." ScienceDaily. www.sciencedaily.com/releases/2000/09/000919114525.htm (accessed October 31, 2014).

Share This



More Earth & Climate News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How A Chorus Led Scientists To A New Frog Species

How A Chorus Led Scientists To A New Frog Species

Newsy (Oct. 30, 2014) A frog noticed by a conservationist on New York's Staten Island has been confirmed as a new species after extensive study and genetic testing. Video provided by Newsy
Powered by NewsLook.com
Raw: Hawaii Lava Approaching Village Road

Raw: Hawaii Lava Approaching Village Road

AP (Oct. 30, 2014) The lava flow on the Big Island of Hawaii was 225 yards from Pahoa Village Road on Wednesday night. The lava is slowing down but still approaching the village. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Endangered Carpathian Ponies Are Making a Comeback in Poland

Endangered Carpathian Ponies Are Making a Comeback in Poland

AFP (Oct. 29, 2014) At the foot of the rugged Carpathian mountains near the Polish-Ukrainian border, ranchers and scientists are trying to protect the Carpathian pony, known as the Hucul in Polish. Duration: 02:17 Video provided by AFP
Powered by NewsLook.com
Deadly Mudslide in Sri Lanka Buries Houses

Deadly Mudslide in Sri Lanka Buries Houses

AP (Oct. 29, 2014) A mudslide triggered by monsoon rains buried scores of workers' houses at a tea plantation in central Sri Lanka on Wednesday, killing at least 10 people and leaving more than 250 missing, an official said. (Oct. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins