Gathering together land-based and satellite data in once place, the researchers found that aerosols in the atmosphere have been increasing over that time, mostly because of airborne pollution.
Obviously, scientists had known aerosols were increasing in some places, but creating this database enhances their ability to see the big picture. Some places, like China, are burdened by heavy air pollution, while some, like Europe, actually brightened a tiny bit in the last three decades. But the planet as a whole sees its air continue to get dirtier.
This study was released right in the middle of a fracas between the Wall Street Journal's editorial board and a think tank called Resources for the Future over the heart of the matter–how we're going to slow down the emissions that created this mess. The Journal bashed President Obama's idea for a carbon cap-and-trade system, saying its burden would fall unduly on mountain and Midwestern states that produce more carbon per capita than coastal areas. (RFF countered that one should look at the consumption of carbon rather than its creation; WSJ said that there's no data for carbon consumption and the whole thing devolved into name-calling using $10 words.)
What is clear is that whether carbon is taxed or traded, someone's going to pay. But we still don't understand exactly how the market's going to sort it out, how much responsibility falls on the corporations producing carbon or how much of the cost will be passed on to customers.
While the fisticuffs at the Journal remind us how little we know about the coming carbon market, the Science study reminds us how much we have to learn about the atmosphere. Aerosols have a weird mix of effects. They can reflect sunlight back out into space, which is one of the reasons that pumping aerosols into the sky is one of the crazy geoengineering schemes on the table, should humans act too late and runaway global warming take over. But they also may absorb energy sometimes, depending on what their composition is.
Atmospheric interactions are complex, and some, like George Will
—who we've touched on before—use this complexity to grind their ax that global warming is a hoax and a bunch of alarmism. Sorry, George—just because something is difficult to understand doesn't mean it's wrong. But the aerosol problem is a reminder that climate models can always be refined as we learn more about the Earth.
Thankfully, some new technologies are on the way. A team of scientists recently developed a radar method to image urban air pollution in 3D
. NASA's Glory satellite, set to launch this fall, will provide data about the global distribution of black carbon and other aerosols over long time periods
. Glory's data could give us an even better idea of how aerosols disperse and linger in our atmosphere—if it makes it to space. The satellite is set to join the same team of orbiters that the Orbiting Carbon Observatory was headed for before its launch failed last month. Keep your fingers crossed for Glory—we need all the data about our home planet we can get.
Even if it's successful, though, and we find out more about how our emissions affect the Earth, we'll probably still be fighting over who should pay to slow them down.