We are increasingly living on a planet of extremes: more heat, more drought, more flooding, bigger storms. More species are at risk of extinction than ever before in humankind’s history. Entire ecosystems are in danger of vanishing. We have entered an age in which humans are the most significant force of global change, in ways that go far beyond altering the climate.

This isn’t necessarily cause for despair. In many ways, it’s a valuable opportunity: to remake the world in a saner, smarter, far more sustainable way. We’re already making progress on some fronts. Global data shows that carbon dioxide emissions have slowed over the past three years, despite economic growth. That’s likely due in part to the rise of less-carbon-intensive fuels and strides in energy efficiency, suggesting the possibility that economic growth can be decoupled from burning fossil fuels. 

But there’s anything but consensus on how exactly to move forward. Is it even possible, for instance, to limit global warming to two degrees Celsius? That was the aim of the 2015 Paris Agreement, which 195 nations joined to slow global warming and its effects. But now that the United States has announced that it will pull out of the agreement, the future of those goals is unclear. 

Scientists believe that fending off a rise of more than two degrees would forestall even more serious global catastrophes—widespread crop failures, insufficient clean water, megafires, crippling refugee crises caused by food shortages, drought, and rising seas. We’ve already passed the one-degree mark.  

Protecting the planet and ensuring a tolerable future for humankind also necessitates a broader lens than just that of climate change. We need to learn to feed ourselves without destroying ecosystems, to harness resources without wiping out the natural world and its myriad inhabitants, to stop making short-sighted decisions that will ultimately hobble us all. It’s time to get serious about how.

Protecting biodiversity

“Conservation” is a term that is often thrown around willy-nilly. It’s a big umbrella, and even deciding exactly what it should cover is an open question. It seems obvious, for example, to say that the critically endangered orangutan should be saved. But even that simple idea turns out to be fraught.

First is the huge question of how to save these charming red apes, which itself opens a Pandora’s box of hurdles. To save orangutans, with whom we share 97 percent of our DNA, we need to protect the tropical forests of Borneo and Sumatra where they live. These forests have been systematically leveled over many years, most recently to produce palm oil for international markets.

Do we protect these forests by pushing for stronger sustainability standards? By applying international pressure on banks that fund deforestation? By trying to stop corruption in Indonesia’s government, which can help drive deforestation and land-grabbing? By paying countries to keep their forests standing?

Then there’s the separate issue of whether trying to save a particular species is even the right approach. If so, how do we decide which ones are “worth” it? An orangutan feels like a no-brainer. But what about a less charismatic species? A beetle, say? Or a frog? Or a tree? There is a growing consensus in the conservation world that we can’t save everything, due to logistics, economics, even basic biological reality. So how do we determine which species most deserve our attention?

Increasingly, scientists say that we shouldn’t think just in terms of individual species, but instead should focus on preserving the habitats where the greatest number of those species live. Another approach would be to protect the largest possible areas of land, so that animals and plants can migrate as climate change causes landscapes to shift around them. The best option is to do all these things. But with limited resources, any path is surely better than none at all.

Feeding the world

Growing our food causes three-quarters of all global deforestation. If current trends continue, another 4 million square miles of land will be cleared by 2050. Agriculture also pollutes vital watersheds, eats up wetlands, pushes out natural ecosystems and endangers native species, all while contributing more than 10 percent of greenhouse gas emissions. 

But we of course need to eat. And a growing world population needs even more food. Producing that food without chewing up land and spewing out too much waste is a crucial challenge.

Just how much we need to increase food production, and how, is another source of debate. A commonly used estimate, released by the United Nations in 2009, is that we need to double food production by 2050. Yet new research published in February suggests an increase of 25 to 70 percent will suffice. Any of these numbers, of course, are oversimplifications. More than a third of the calories produced by food crops are used to feed livestock, yet only 12 percent of those same calories ultimately end up feeding people. So some experts argue that reducing meat consumption is a simple—and necessary—fix. 

“The vast majority of increasing demand for food is not from population growth,” says Jon Foley, executive director of the California Academy of Sciences and an expert on global agriculture. “That’s insignificant. It’s diet.”

However, the expanding middle class in countries like China, India, Indonesia and Brazil are demanding more protein. Persuading the entire world to go vegetarian may be a tall, if not impossible, order, but getting people to switch from grain-fed beef to chicken would be an improvement—and might be achievable. And it could make a huge difference, since raising livestock contributes up to 18 percent of all greenhouse gas emissions, and livestock production takes up 75 percent of all agricultural land.

“If two billion more people want to eat like Americans,” says Foley, “we’re done.”

There’s also the question of geography. In some places, agricultural yields—how much food a certain amount of land provides—are far below the global average. So some experts say we should focus on increasing production in those regions of the world first. “If you could just bring modern agriculture to places that are underperforming, that would get you halfway there,” says Peter Kareiva, director of UCLA’s Institute of the Environment and Sustainability.

Closing this “yield gap," which is the difference between a crop’s potential yield in a particular place and its actual yield based on the farming methods being used, in many parts of Africa and Latin America could go a long way toward filling the world’s larders. Raising yields for 16 crops to 75 percent of their potential via simple tools like specially adapted seeds, fertilizer, irrigation and microcredit could increase global food supplies by more than a quarter.

Getting to zero emissions

In March, a team of scientists and researchers from the Stockholm Resilience Centre and other institutions published a high-profile paper in the journal Science, proposing a detailed roadmap for capping warming at two degrees. To meet this obligation, every industrialized country needs to massively slash greenhouse gas emissions, starting now. But the scientists argued in the Science article that “alarming inconsistencies remain between science-based targets and national commitments” and proposed a “carbon law” that would halve carbon dioxide emissions every decade, starting in the 2020s.

Over the next three years, they say, government subsidies to the fossil fuel industry worldwide must shrink from $500 to $600 billion a year to nil. From 2020 to 2030, carbon cap-and-trade and other similar policy-based carbon-reduction systems must ramp way up, as does investment in things like batteries, methods to suck CO2 from the air and stash it out of harm’s way, and what they call “super-smart power grids.” By 2030, internal combustion engines have to be on the wane.

With a mix of massive research-and-development funding, strong government policies, herculean corporate efforts, and all-around innovative action in fields ranging from construction to air travel to agriculture, we could be seeing the last days of oil by 2040. 

It all sounds eminently doable—but big questions loom about how to proceed. Should nuclear energy be part of our energy future? How much should we invest in continuing to develop natural gas, which has lower emissions than oil or coal but is still a fossil fuel? Is replacing coal with natural gas a necessary step, or akin to taking an aspirin when you really need open-heart surgery?

Moreover, can the world achieve anything close to the Paris commitments without the United States as a participant? Without the U.S. on board, countries like China and India will have to move to the forefront in unprecedented ways. China, the world’s biggest manufacturer of solar panels, seems ready to do this. But not everyone is convinced that China can commit to the task, given that the country is still opening coal plants around the world even as it cuts down on emissions on its own turf.

Saving the oceans

The issues involving oceans are complex these vast bodies of water defy boundaries: They are at once local, national, and international. Oceans are so vast, mysterious, and wild that it’s difficult for humans to fathom the degree to which our activity is affecting them. But the fact is that we are endangering the seas in many different ways, which in turn endangers our own food source and has other far-reaching implications.

Climate change is causing oceans to acidify, killing off coral reefs—vitally important ecosystems—including parts of the massive Great Barrier Reef. Warming temperatures are also causing currents to shift and marine species to migrate, which interferes with fundamental food webs. Then there’s pollution – such as runoff from agriculture, which creates dead zones, and plastics, including the tiny micro-beads that are turning up in sand and sea-creature stomachs virtually everywhere scientists look. And then, of course, there’s overfishing, which has perhaps gained more public attention than any other marine issue.

One popular tool for solving this last problem is marine protected areas, akin to national parks or nature preserves on land. In these areas, parts of the ocean are cordoned off and fishing is prohibited, with the idea being that species will get a chance to thrive. They might also become  more resilient to climate change, if only because of the absence of other stressors. Some scientists are calling for an expansion of the protected-area concept, which is aimed largely at protecting fish stocks.

“We still very much manage the ocean on a single-species model, like we manage a fishery,” says Cassandra Brooks, an ocean policy researcher at Stanford University. “We haven’t done a very good job of managing the ecosystem.”

Doing a better job of responsibly managing the entire ocean ecosystem would require much more monitoring and enforcement than currently exists, as well as coordination across multiple government agencies. Brooks is part of a group of scientists who are proposing the idea of closing the high seas—areas beyond national jurisdiction, which represent up to 70 percent of the planet’s oceans—to fishing. This might, researchers say, provide countries with an incentive to fish more responsibly within their legal waters.

Which leaves us with the next big question: How to enforce such a rule?

Mobilizing the masses

How can we get more people around the world to care about protecting the planet? This may be the toughest question of all. Many environmental organizations are now working on projects traditionally regarded as humanitarian or development work: education for girls, micro-loans for women, family planning. This is because economic welfare and education are often tied to concerns for the environment. If you don’t know where your next meal is coming from, it’s hard to be concerned about protecting a rainforest, maintaining fish stocks or saving orangutans from extinction.

But what about here in the U.S., where the majority of Americans—62 percent, according to a 2017 Gallup poll—accept that human-caused climate change is underway but still place environmental concerns relatively low on their list of priorities? For at least two decades, scientists, journalists, environmental activists, and many politicians have been grappling with ways to make clear the urgency of the challenge we face.

But so far, no one seems to have hit on a winning solution. It’s possible things might get so disastrous—floods, fires, heat waves—that action will becomes unavoidable. After all, the Clean Water Act of 1972 was partly spurred by an Ohio river so polluted it caught fire. And this could happen sooner than most of us think. But will even that be soon enough to prevent irreversible calamity?

The time to do nothing has long since passed. The planet is in peril, and to save it—and ourselves—we need do the hard work now.