A closer look at climate change data

Source: United Nations Framework Convention on Climate Change

Source: United Nations Framework Convention on Climate Change

It’s been called “the world's greatest diplomatic success.” The recent Paris Climate Conference (COP21) brought together nearly 200 countries with a plan designed to limit greenhouse gas emissions and put a cap on global warming.

But before you walk to the farmer’s market to celebrate with a smoothie (made from locally sourced seasonal fruit, of course), let’s take a closer look at the information—and misinformation—hidden in some of the climate data we’ve seen this past week, and offer a few questions you may want to ask as a smart consumer of data.

Which data matters the most? In terms of total greenhouse gas emissions, India is the third-largest contributor on the planet, higher than Canada, Japan and other industrial powerhouses. But India has approximately 10 times the population of Japan. In fact, if you look at emissions another way—on a per capita basis—India is near the bottom of the list, along with Swaziland and Albania. If your goal is to limit emissions caused by human activity, you could come up with different solutions to the problem simply by changing the way you look at the data.

Is all the data being represented equally? There were almost 200 countries involved in the historic agreement. In a simple count (or list) of attendees, each one is the same. But when it comes to climate change, we’ve already seen that all countries are not equal. Two of those countries (China and the US) account for more than one-third of the world’s greenhouse gas emissions. Treating them all equally obscures that fact.

From where does the data come? The World Resource Institute (WRI)—an organization that tracks global greenhouse gas emissions—published a 26-page paper explaining how they collect emissions data from “respected research centers, government agencies, and international bodies.” Which ones? How reputable are they? Which greenhouse gases are being measured? Unless you read the report, you’ll probably never know.  

How old is the data? The most recent data for total greenhouse gas emissions on WRI’s CAIT Climate Data Explorer appears to be from 2012. That’s not surprising, given the efforts it takes to gather and compile the data. But it means that the information used to make decisions is (and will likely continue to be) 2-3 years behind the times. If you don’t have access to real-time data, you may need to extrapolate, estimate or make assumptions about trends in the data.

How is the data aggregated? Greenhouse gas emissions are measured on a country-by-country basis. But aggregating data can mask important variations. For example, a town that’s home to a coal plant may emit more greenhouse gases than an otherwise identical town without such a facility, given that the combustion of coal and other fossil fuels for electricity is linked to carbon dioxide emissions in the US. Aggregating the data is a common practice—and one you’ll hear about ad nauseum with the upcoming US presidential elections, given that “red states” and “blue states” are a consequence of data aggregation via the Electoral College system.

Are visualizations distorting the data? Philip Bump from the Washington Post wrote an insightful piece about how a National Review chart on climate change “hides the actual change in the temperatures” (according to Bump) by using a scale roughly 50 times greater than the changes in the data. Whether it’s adjusting scales on a chart, showing cumulative rather than incremental data, or using the size of a circle to represent data (without saying whether the circle’s diameter or area is the relevant factor), there are seemingly countless ways to change the story of the data through visual representation.   

Why are there so many round numbers? Throughout the United Nations Framework Convention on Climate Change document outlining the agreement, we see round figures when it comes to temperature goals (a maximum 2°C rise), emissions projections (40 gigatonnes), milestone years (2020, 2025, and 2030) and financial targets ($100 billion in financing to assist developing countries). “Round numbers are intrinsically motivating to us, even if there’s no obvious reward for reaching them,” noted Scientific American, citing a study from Psychological Science. That begs the question: is a 2°C maximum temperature change the most appropriate figure—or just the most appealing one, psychologically speaking, within a range of acceptable temperature changes? Think of it this way: If the temperatures were in Fahrenheit instead of Celsius, would we be talking about a 3.6°F difference (roughly equivalent to 2°C), or would it be rounded to 3.5°F (or even 4°F)?

Bottom line? If you want to help save the planet, there’s still a lot more work to do. But if your goal is to understand the data behind the headlines, you’re definitely getting warmer.