How Worried Should We Be About Climate Change?

The United Nations recently held their climate summit in New York City. A few days ahead of the event, more than 300,000 people joined a peaceful march in Manhattan to call attention to the issue of climate change. Secretary Of State John Kerry recently argued that the problem of climate change should be addressed with the same immediacy as Ebola or ISIS. So, putting politics aside, how serious is this issue? Well, there’s an incredible amount of statistical evidence that illustrates the severity of climate change. But instead of getting mired down in talk about ice caps and polar bear populations, let’s just discuss what the UN Climate Summit is really about: air pollution. The UN is meeting in hopes of signing a deal that could cut down on carbon emissions worldwide.

Just to be clear, we are talking about cars and our dependence on oil, but we’re also talking about things like coal power. Climate change is a pressing issue now because there are nations, chief among them China, that are actively pumping carbon into the environment on an enormous scale. According to the Global Carbon Project, China alone accounts for 28% of the world’s total carbon emissions. And they increased their emissions last year by 4.2%, which increased global emissions worldwide, by 2.3%. In other words, year over year – the situation is getting worse, not better. The ultimate goal of this meeting is to establish a plan to reduce these emissions. And one way to do that – is switching away from coal and fossil fuels, to cleaner forms of energy; a switch that some economists and ecologists now argue could also help developing countries, like China, save money in the long run.

They also argue that it would benefit not just the environment, but also the health of the people in those nations. The argument against committing to cleaner energy is that it requires an enormous initial investment and could potentially slow down economic progress. The problem is that the very nations that need economic progress most, are also the nations that emit the most carbon. It’s a catch-22, and a large part of why an agreement still hasn’t been reached. To find out more about what’s going on in China, check out our video on the conflict between China and the Tibetan Independence movement. Or watch our other video on How Powerful China really is. Remember we upload new videos five days a week, so please subscribe..

Why cities should plant more trees

Search Google Earth for China and you’ll see this. But an unedited satellite photo might look more like this. That gray smudge is air pollution and it’s coming from Chinese cars, factories, and power plants. But it’s not only here. In cities around the world, air pollution is a big problem. A majority of humans now live in cities and that number is only going to rise, which means more cars, more factories, and more power plants. As officials explore options for fighting air pollution, there is one tool that is often overlooked: trees. Cities are centers of industry, but the resulting pollution is filling our lungs and making us sick. One major culprit is particulate matter: airborne particles of dust, soot and smoke that are released when we burn fossil fuels or kicked up during construction and farming.

When we inhale them, they can cause asthma and they can also enter our bloodstream to cause strokes and even death. Experts estimate that outdoor air pollution kills over three million people a year and as cities grow, leaders are funding creative—and often expensive—solutions for the problem. In London, the mayor spent over a million pounds spraying city streets with an adhesive that was supposed to glue pollutants to the road. and in the Netherlands, designers have created a giant air purifier they call “The Smog Free Tower”, which is cool, but there is another, simpler solution… A new report from The Nature Conservancy shows that planting trees can be a cost-effective way to improve public health, which they do in two ways: First, a tree removes particulate matter when polluted air blows through its branches.

The particulate matter settles on the leaves and when it rains the dust is washed down the gutter so we don’t inhale it. Second, trees cool temperatures by providing shade and releasing water through photosynthesis, which cools summer temperatures by about two to four degrees fahrenheit. But there is a catch! Trees can only clean and cool the air within a close radius: about one hundred feet, so city officials need to be careful where they plant. Officials can maximize pollution reduction by planting trees where population density and air pollution overlap. The Nature Conservancy report uses data from Washington D.C. to create a map showing where planting trees will have the highest return on investment. And some trees work better than others: trees with larger, stickier leaves, like maples and elms are more effective, but they also need to be considered within the larger ecosystem.

Compared to DC, many cities around the world have even more to gain from planting trees: this map shows where return on investment is highest for reducing particulate matter. With proper targeting, planting trees can be just as cost-effective as other strategies like converting public transportation to use less diesel fuel. But there is one major limiting factor: water access. What might work in Boston, will be less feasible in a city like Doha, Qatar, where water is a scarce resource. And on top of that, many mayors don’t yet think of trees as a public health resource. Trees might not look like giant air filters, but that’s exactly what they are, and the sooner we start thinking of them that way, the sooner the air we breathe might be cooler and cleaner in cities around the world..