As family vacations and summer trips home loom near—and as hurricane season and volatile summertime weather approach—you may find yourself in the position of defending the claim you thought everyone had come around to by now: yes, climate change does exist. It's best to be prepared. Luckily, data scientists and designers have done half the work for you by synthesizing overwhelming and often inaccessible data into easy-to-understand (and hard-to-deny) visualizations of the science behind global warming.
Here are four of our favorites—keep them in your back pocket for your next baffling exchange about whether global warming is a hoax.
The Science: Arctic sea ice is naturally moderated by the amount of sunlight it receives—it grows in the winter and shrinks in the summer. But as the oceans heat up due to global warming, Arctic sea ice has been locked in a downward spiral, retreating more and more every year. Essentially, it's a big feedback loop: ice thins out when it melts, making it less reflective. Heat gets trapped underneath ice and causes it to melt further. As the ocean absorbs heat it accelerates global warming.
According to NASA researchers, ice has retreated 12% per decade since the 1970s. The decline has rapidly accelerated since 2007. In March 2016, sea ice extent hit a record low for the second year in a row.
The Design: When cartographers from the National Geographic set out to redraw the 10th edition of its highly regarded atlas, the Arctic portion of the map had to be dramatically redrawn because of this data. In fact, it was the biggest change the publication has had to make to its atlas since the break up of the Soviet Union. After President Obama pointed this fact out in a 2015 speech, the National Geographic compiled the Arctic portion of atlases from 1999 to 2014 to show how much of the Arctic had to be altered over just 15 years.
The Takeaway: Data can be hard to understand and easy to ignore. But it's difficult to deny the shrinking sea ice when you watch it unfold in GIF format. These are atlases that are meticulously drawn each year by some of the world's best cartographers based on hard data. As Juan José Valdés, one of the map's cartographers puts it, "You hear reports all the time in the media about this. Until you have a hard-copy map in your hand, the message doesn't really hit home."
The Science: The year of 2015 was the warmest on record, thanks in part to El Niño, as well as an unusually strong polar vortex. However, data points to climate change as the overwhelming contributor: as carbon dioxide and other greenhouse gases accumulate in the atmosphere, the planet’s temperature continues to rise. If they continue at this rate, in the year 2100, it won't be a few weirdly warm winter months—these temperatures will be the norm. Boston winters, for instance, will feel like those in Marietta, Georgia. New York will be as warm as Killeen, Texas.
The Design: This information comes from the researchers and journalists over at Climate Central, who used data from DayMet to calculate 1,001 American cities' average winter temperatures and PRISM for their summer temperatures. They then compared these temperatures to what is forecast for these same areas in 2100, according to the UN's RCP8.5 scenario—a model which predicts what will happen to the Earth's temperatures if we don't cut back on CO2 emissions at all—and mapped it. Type in your city and the map will display what the weather will be like in 2100: the number of days below freezing for the winter and average temperature for the summer. It then draws a line to a present-day city with comparable weather conditions now to drive the point home.
The Takeaway: The map takes a somewhat vague notion (rising temperatures) and makes it easily digestible—and hard to dispute—by drawing comparisons between cities. That the Chicago winter of 2100 will have only 52 nights below freezing may not mean much to the average person. But to say Chicago winters will soon be the same as the winters in Vestavia Hills, Alabama—that packs more of a punch.
The Science: The melting of sea ice (like that described above) doesn't contribute much to sea level rise because it's already in the ocean. The melting of land ice (like glaciers) into the ocean, however, is a major cause of rising sea levels. Over the last 20 years, the annual rate of rise has been 0.13 inches a year, which is roughly twice the average speed of the preceding 80 years. If sea levels continue to rise at this rate, coastal and low-lying cities will be in danger of disappearing underwater over the course of this century.
The Design: If the prospect of entire coastal regions being submerged in water isn't evocative enough, the Dutch designer Daan Roosegaarde visualized it in an eerie virtual flood. In a field in Westervoort, a town in eastern Netherlands that's particularly susceptible to flooding, Roosegaard set up lenses that project waves of blue light overhead. The installation creates a kind of translucent blue ceiling that swirls and creates waves like water. It's beautiful and mesmerizing, but it also represents the danger of rising sea levels and massive flooding.
The Takeaway: Because of global warming, sea levels are rising. Without significant engineering, cities on the coast will face major destruction. Cities will be underwater—and unlike Roosegaard's interpretation, the real-life version won't be whimsical.
The Science: Last December, 190 countries gathered at COP21 near Paris to hammer out an international agreement for climate change. The outcome was the Paris Agreement, a protocol that set a goal of limiting global warming to less than 2 degrees Celsius. But one of the major discussion points of the conference regarded developing countries that were most vulnerable to global warming but the least equipped financially to regulate it. A 2014 map from the Guardian illustrates which countries contribute the most to carbon emissions, both currently and historically, and which are the most vulnerable to the effects of global warming.
The Design: The Guardian created the map ahead of the 2014 United Nations climate change summit in New York, but the information still holds true. It shows that, in many cases, the countries suffering the most from carbon-related climate change aren't the ones emitting the most fossil fuels. Users can select from a list of categories in a side legend—fossil fuel extraction, CO2 emissions, and other measures—and the countries on the map swell or shrink to represent their proportional responsibility, as well as their vulnerability in terms of displacement, poverty, and rising sea levels.
The Takeaway: The map elegantly visualizes that the countries most vulnerable to climate change are most often not in a position to stop it, since they are not the ones causing the damage. The United States and China, for example, emit the most fossil fuels, but the places that are most at risk for being displaced or harmed by climate change are countries like Ethiopia, which consumes a comparatively small amount of fossil fuels but still gets hit the hardest with the effects. The map is fun to play around with—it's goofy and cartoonish to watch the map warp into unfamiliar proportions—but it's also a salient reminder: Climate change not only affects the planet in terms of temperatures and rising sea levels, it also has geopolitical consequences.