UPDATE: Today, the American Meteorological Society released its 2012 State of the Climate report, with some pretty scary information: 2012 was one of the top ten hottest years ever recorded. Kathryn D. Sullivan, Ph.D. of the National Oceanic and Atmospheric Administration explained that "many of the events that made 2012 such an interesting year are part of the long-term trends we see in a changing and varying climate — carbon levels are climbing, sea levels are rising, Arctic sea ice is melting, and our planet as a whole is becoming a warmer place." Sea levels also reached a record high after decreasing in 2011. You can read the full report here, or some highlights and explanations over at the NOAA website.
Originally published on July 27: Are you slowly melting while reading this sentence? Yeah, us too. There's no doubt that it has been a hot (and cold) summer so far, and we've only just started July. Frankly, we'd rather not even think about August, and what it has in store for us.
Plus, remember the topsy-turvy winter we had? The constant (often unfulfilled) threat of crazy storms here in NYC coupled with, oh say, 16-inch snowfalls in the middle of May in Minnesota, had definitely kept us all on our toes. All told, it makes for a pretty good story, and a lot of excellent fodder for whining. While we might have a tendency to jump to conclusions and call it global warming, we opted to do a bit of research, instead. So, what's the real story with all this bonkers weather, you ask?
We talked to Dr. Sarah Kapnick, a postdoctoral research associate at Princeton University's Program for Atmospheric and Ocean Sciences, to get the scoop on the often misrepresented, easily distorted truth of climate change. No politics, no partisanship: This user's guide is about pure science — but broken down for the uninitiated. And, when it comes to global warming, the scientific opinion is notably different from the political picture. According to a report by the Yale Project on Climate Change Communication, 97% of peer-reviewed papers by climate scientists agree that climate change is happening and is caused by humans. And yet, only 41% of Americans believe that. The rest of the surveyed group responded "no" or "don't know"; and among that group, 4% even stated that "most scientists think global warming is not happening." Yikes.
Kapnick, like most of the scientific community, agrees that there is simply no doubt that the climate is changing as a direct result of human activity — that warming is, to use official terminology, anthropogenic. "Humans influence the climate in a number of ways. The one that's most known — or at least, most debated — by the general public is greenhouse gas emissions." That's the release of a number of gases, primarily carbon dioxide from electricity generation (but also from cars and methane from livestock waste) into the atmosphere. One important greenhouse gas indicator, the Keeling Curve, recently reached an unprecedented high in its documentation of carbon dioxide in the atmosphere. As of June 2, the Mauna Loa observatory in Hawaii (where Keeling Curve data is measured) recorded its highest-ever carbon dioxide concentration, at 400 ppm.
But, there's more to the story than just greenhouse gases. Another way humans change the climate is through land use. Deforestation, concrete jungles, and other such things have a considerable impact on the atmosphere. "Changing the surface cover of the Earth changes the Earth's albedo — how much the Earth reflects sunlight." Albedo is higher in areas with ice cover, and lower in areas with, for example, thick forests. Human land use also alters the amount of vegetation (which locks away carbon dioxide), and changes the amount of dust in the atmosphere.
And finally, a third means of anthropogenic change comes in the form of aerosols. Though we might reserve the term for hairspray, in scientific language, it refers to "tiny particles that are suspended in the air. They can make the climate warmer or cooler depending on the type of particle, and where it is in the atmosphere."
Land use and aerosols can also have very specific, local effects, compared to the global effect of greenhouse gases. But overall, Kapnick says, models using data from as far back as 1861 indicate a rise in temperatures that is a combined result of all these factors.
These three categories, and the many activities that contribute to them, provide a clear picture of what humans are doing that changes the environment. But exactly what is happening as a result of these behaviors? What's the connection between things like greenhouse gases, land use, and aerosols and the feeling that it's getting hotter and hotter every summer — not to mention the seeming increase in hurricanes and tornadoes? Well, seeking the simplest explanation, Kapnick helped us break it down into three major subsets of climate change as a whole. Click through for a troublesome look at what's to come.
Ocean levels are rising. A common misconception is that water levels rise because sea ice melts. More water in the ocean means higher sea levels, right? Well, not quite. While the levels are rising, sea ice melting into the ocean is not actually the cause of it. Ice molecules have a higher volume than water, and therefore when ice melts, there is actually more space for water in its place. Sea levels rise primarily as a result of two things: Changes in ocean density (or thermal expansion), and melting land glaciers. As the atmosphere warms, the surface level of the ocean also warms, and over hundreds of years, it mixes with the cooler, deeper water. "Slowly," Kapnick explains, "the ocean has an overturning circulation, and the water is warmed. Water density is based on temperature and salinity, and as it warms, it expands." Reason number two has to do with glaciers (landlocked frozen water that remains largely frozen through the summer, the most prominent of which are Greenland and Antarctica, as well as the Himalaya region and the Alaskan coast). Most of these glaciers are retreating, and the melted water goes into the ocean, in turn causing further rise. Both glaciers and sea ice have a lower salt level, and that addition of fresh water to the ocean also contributes to changes in ocean-water density. For places like New York City and Florida, where swamps have been filled and people live close to sea level, that means more flooding — flooding that may eventually become permanent, rather than seasonal.
The air is getting hotter. As we previously mentioned, the atmosphere is primarily effected by greenhouse gas emissions, changes in land use (and resulting changes in albedo), and aerosols. As you may have noticed the last time you came back from the beach looking like a lobster, the sun is pretty hot — and that heat goes into the Earth. Ideally, it should be radiated back out into the air, and eventually, into space. But, when the air is full of carbon dioxide and various aerosols, the heat is effectively trapped — not permanently, but it is prevented from radiating out as quickly and efficiently as it should. And, when the Earth is radiating even more heat because of changes in surface cover (for example, fewer glaciers and less snow, but more concrete), well, that just compounds the problem. For an idea of how this is manifested in contemporary weather patterns, check out this study published by the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory, which found that heat waves are increasing not only in frequency, but in duration.
Annual snowfall is changing, in more ways than one. Temperatures are increasing in snowy regions, and snowfall itself is, consequently, decreasing across most of the United States. Snowfall is Kapnick's own particular area of study, and she sees it as something of a metonymy for climate change as a whole. "In the American West, we've seen that most mountains have less snow on April 1. But, it's not just the amount of snow that falls, it's also how early it melts." Less snowfall and ice cover can significantly change biodiversity by disrupting the habitats of some creatures, not to mention the environments of foods you love (including, for example, apples) that can only properly be harvested if temperatures remain consistently cold, then at spring temperatures, and then move at an even pace into summer. As this (morbidly) fascinating article points out, this could have a drastic effect for many aspects of agriculture.
And what about that favorite of post-apocalyptic movies, extreme weather? Kapnick is careful to point out that "one of the hardest things for climate scientists to communicate is the uncertainty of our projections about climate change. There's much more certainty among the models that temperature, overall, will increase. For ocean sea levels, we project that they'll continue to rise." Basically, that means there is a certain degree of confidence in the models, but they're not perfect — and when it comes to storm systems, things are even more muddy, as this report indicates. "There's a lot of uncertainty around, for example, hurricanes and what changes we may see in their frequency. However, the effect that hurricanes have on the ocean is a concern, particularly for cities like New York." The effects of a storm like Superstorm Sandy are quite different based on ocean levels. "Even if the number and intensity of hurricanes remains the same in the future," Kapnick says, "we're more susceptible to storm surge and infrastructural damage because of rising sea levels." Data about storms, tornadoes, and the like is also flawed because until the rise of modern satellite technology, scientists could only account for storms that hit places where people lived. Plus, what scientists call an "average" year is based on 30 years of data compiled together. "In New York, we got two bad storms in a row. We can't say for certain what that says about climate change, but it does mean that we need to build more adaptable infrastructure. We remember what we've experienced recently, it's natural for us to think things are increasing."
But here's the truly troubling part. Even if we're being optimistic and believe that this article has increased the percentage of the American public that believes in global warming by some tiny fraction, that doesn't do a ton to help us course correct. According to Kapnick, even if we were to completely stop greenhouse emissions today, warming would continue for years before beginning to reverse (as would the effects on snowfall, ocean levels, and the like). Uh oh.
But, that doesn't mean we all give up. Interested in learning what you can do to help mitigate the effects of climate change? First of all, you can dig a little deeper into the data with this amazing resource (or try this one, too; or this tool for New York state residents...okay, okay, we'll stop). You can also spread the word about initiatives that will help reduce the effects of climate change on people's lives — like NYC Mayor Michael Bloomberg's recent flood plan, or support President Obama's comprehensive new plan. Plus, the EPA provides a number of easy, feasible tips that you can put to action right away in your home, office, and community. Or, if you're ready to think about the global picture of climate change, you can educate yourself about the effects of developing nations — where sustainability and clean energy are even less available than they are here — on the future of global warming. The United Kingdom has been particularly active with initiatives to couch economic and infrastructural development in the context of climate change as it is now, and as it is predicted to be in the future if current levels continue. As for little old you, you can donate to charities like the WWF and the Clinton Foundation.
Most of all, as far as discussion is concerned, you can start reframing this conversation in your own life as a scientific issue, rather than a political one. Politics will always have a part to play in the fight against climate change, but as citizens of a democratic country, we all have a responsibility to engage in reasoned and informed discussion. Because this isn't about liberals or conservatives or scientists or laymen winning an argument — it's about humanity earning the right to remain on a habitable, wonderful planet. That, if you ask us, is something we can all agree on.
Illustrated by Ly Ngo