Photo by Nicolò Lazzati on This post originally appeared on The Huffington Post.

By Angel Hsu and Carlin Rosengarten

Last year was the hottest year on record — and by a wide margin, too. By early summer atmospheric CO2 concentrations silently ticked past 400 parts per million (ppm) for the first time in a million years, an outcome of fossil fuel combustion. The planet shows other troubling signs of rapid environmental change, including ocean acidification and warming, dwindling polar ice, and dramatic biodiversity loss, to name a few.

The 2016 Environmental Performance Index (EPI), like no other study, captures the current state of environmental governance and gives a snapshot of the world’s human and ecological health. Launched at World Economic Forum’s Annual Meeting in Davos, Switzerland last week, the 2016 EPI ranks 180 nations, representing 99 percent of the world’s population, on their environmental performance in two broad categories: protection of human health and protection of ecosystems. Within these two objectives the EPI scores countries in nine issue areas comprised of 20 environmental indicators. Beyond country rankings, the project’s results provide a data-rich narrative about the world’s environment and national-level environmental policy.

So what does the 2016 EPI find?

Progress in many areas, calamitous decline and degradation in others. First, some good news: more people have access to water that is safe to drink than ever before — the number of people lacking access to clean water was nearly halved from 1 billion in 2000 to 550 million in 2015. And because of this improved access, waterborne illnesses today cause only 2 percent of human deaths worldwide.

Now for the bad news: our air is getting worse. The air we breathe is making us sick and blunting our productivity. There has been a steady increase in air pollution over the last decade and thus in human exposure to toxic air. More than 3.5 billion people — half the world’s population — breathe air deemed unsafe by World Health Organization standards. Air pollution is now responsible for 10 percent of all human deaths. The EPI shows that more than half of China and South Korea’s populations, for instance, are exposed to unsafe levels of pernicious air pollutants. In India and Nepal the proportion is nearly three-quarters.

Air’s decline and water’s improvement tell an intuitive story. As nations grow wealthier, governments invest in water treatment and distribution infrastructure. Economic development is thus associated with improved water quality and access. With economic growth comes industrialization and urbanization, which lead, of course, to more air pollution and an increase in human exposure. This is why we see improvements in water indicators in rapidly growing economies, like China and India, alongside worsening air quality.

Unsafe air, however, is not solely a problem for developing nations — it is a global issue. Nitrogen-oxide compounds (NOx), which are leading agents of respiratory diseases in humans, foul the air in Belgium, the Netherlands, and Germany, where NOx levels, driven by the widespread use of diesel fuels in vehicles, exceed China’s. New laws are set to drastically reduce tailpipe emissions in Europe, while in China and India, coal-fired power plants and the introduction every day of thousands of new vehicles to the roads continues to push NOx levels beyond what humans can safely tolerate.

Other narratives contained in the 2016 EPI point to a paradox of modernization. For instance, while habitat protection, both terrestrial and marine, is at an all-time high — more than 15 percent of the world’s land area and 8 percent of marine habitats now have official protection — biodiversity continues to decline at a staggering clip, with the vertebrate extinction rate at least 100 times the natural, or “background,” rate. Fisheries too are in dire straits, with more than a third of the oceans fish stocks overexploited or collapsed.

But what grab the attention of national governments around the world are the Index’s country rankings. While it is not very useful to compare each nation to all the others, comparing peer countries is a fruitful way to draw meaning from the ranks and scores. Nordic countries took the top four spots in the 2016 EPI with Finland leading the pack, while Somalia and other troubled states occupy the bottom. The rankings show that environmental performance is essentially a governance issue. If a nation does not care for its environment it also does not care for its people. In the EPI’s ranks we see how environmental indicators are proxies for measures of livability and human wellbeing.

The 2016 EPI, full of data and figures, is a text for interpreting the world’s environmental status. The Index reports on the current state of knowledge and also points to areas where information is scarce and the science is poor. Better data is our goal. All areas of environmental measurement will have to be enhanced and their capacities enlarged if we want to inform effective policy, improve management, and achieve the ambitions set forth by the SDGs and Paris Climate Agreement.

Some nations are on a path to sustained environmental and human health, while many countries struggle to meet essential needs. To manage our shared planet, we have to take stock of where we stand. Setting goals is important but insufficient. Determining how to achieve these goals and putting new ideas into action are greater challenges. The EPI is designed to catalyze this process, using the best available data to project the world’s environmental conditions for everyone to see. We measure change so that people can affect the world in ways beneficial to their environments and to themselves.