How long does humanity have left

While some species can certainly adapt to the changes taking place in our environment, humans are no longer a mere species that follows Darwinian evolution but a much larger force that has come to drive evolution on this planet. Studies have shown that for most species, evolutionary adaptation is not expected to be sufficiently rapid to buffer the effects of environmental changes being wrought by human activity. And our own species will be no exception to this. While there is no proof that we will destroy ourselves, there are clear indications that we ignore the effects at our own peril.

For example, some of the mass extinctions in the Earth's history are related to acidification of oceans. The oceans may be acidifying faster today than they did in the last million years, primarily due to human activities. Can the species we share the planet with adapt fast enough to cope with the new world we are creating for them?

Widespread degradation of ecosystems threatens the conditions of life on Earth, in particular the long-term survival of our own species. Our impact on the planet is much is deeper than carbon footprints or global warming. It points to a future where the effects of anthropogenic matter will take over — if it hasn't already — the identity of the Earth and its life.

In the face of this, humans themselves might lose out in the evolutionary race. Eliminating materials like concrete or plastic or replacing them with alternatives is not going to address the fundamental problem with human attitudes and our unparalleled appetite for more. This is exactly where materialism can seamlessly transform into a known unknown risk factor in global catastrophe.

The myriad of ways in which it can turn this planet into a mundane world is something our civilisation has never experienced before. In the absence of a fully secure evolutionary shield, we could depend on our intelligence to survive. Nevertheless, as Abraham Loeb, professor of science at Harvard University and an astronomer who is searching for dead cosmic civilisations puts it, "the mark of intelligence is the ability to promote a better future".

The story of Bhasmasura in Hindu Mythology offers an eerie parallel to the impact of materialism. As a devotee of Lord Shiva , he obtains a boon from Shiva, which empowers him to turn anyone into ashes with a mere touch on the head. Immediately after gaining this magical ability, he tries to test it on Shiva himself. Shiva manages to escape, the story goes. But humans may not be lucky enough to flee from their own actions.

Unless, we offer a different vision rooted in reduction of consumption, the flames of our own materialism might consume both us and our Pale Blue Dot.

Climate-change skeptics point out that the planet has warmed and cooled many times before, but the climate window that has allowed for human life is very narrow, even by the standards of planetary history. This century, and especially in the tropics, the pain points will pinch much more quickly even than an increase of seven degrees. At present, most regions reach a wet-bulb maximum of 26 or 27 degrees Celsius; the true red line for habitability is 35 degrees.

What is called heat stress comes much sooner. Since , the planet has experienced a fold increase in the number of places experiencing dangerous or extreme heat; a bigger increase is to come. The five warmest summers in Europe since have all occurred since , and soon, the IPCC warns, simply being outdoors that time of year will be unhealthy for much of the globe.

Even if we meet the Paris goals of two degrees warming, cities like Karachi and Kolkata will become close to uninhabitable, annually encountering deadly heat waves like those that crippled them in At four degrees, the deadly European heat wave of , which killed as many as 2, people a day, will be a normal summer. At six, according to an assessment focused only on effects within the U.

By the end of the century, the World Bank has estimated, the coolest months in tropical South America, Africa, and the Pacific are likely to be warmer than the warmest months at the end of the 20th century. Air-conditioning can help but will ultimately only add to the carbon problem; plus, the climate-controlled malls of the Arab emirates aside, it is not remotely plausible to wholesale air-condition all the hottest parts of the world, many of them also the poorest.

And indeed, the crisis will be most dramatic across the Middle East and Persian Gulf, where in the heat index registered temperatures as high as degrees Fahrenheit.

As soon as several decades from now, the hajj will become physically impossible for the 2 million Muslims who make the pilgrimage each year. It is not just the hajj, and it is not just Mecca; heat is already killing us. In the sugarcane region of El Salvador, as much as one-fifth of the population has chronic kidney disease, including over a quarter of the men, the presumed result of dehydration from working the fields they were able to comfortably harvest as recently as two decades ago.

With dialysis, which is expensive, those with kidney failure can expect to live five years; without it, life expectancy is in the weeks. Of course, heat stress promises to pummel us in places other than our kidneys, too. As I type that sentence, in the California desert in mid-June, it is degrees outside my door. It is not a record high. Praying for cornfields in the tundra. Climates differ and plants vary, but the basic rule for staple cereal crops grown at optimal temperature is that for every degree of warming, yields decline by 10 percent.

Some estimates run as high as 15 or even 17 percent. Which means that if the planet is five degrees warmer at the end of the century, we may have as many as 50 percent more people to feed and 50 percent less grain to give them. And proteins are worse: It takes 16 calories of grain to produce just a single calorie of hamburger meat, butchered from a cow that spent its life polluting the climate with methane farts.

Pollyannaish plant physiologists will point out that the cereal-crop math applies only to those regions already at peak growing temperature, and they are right — theoretically, a warmer climate will make it easier to grow corn in Greenland. But as the pathbreaking work by Rosamond Naylor and David Battisti has shown, the tropics are already too hot to efficiently grow grain, and those places where grain is produced today are already at optimal growing temperature — which means even a small warming will push them down the slope of declining productivity.

Precipitation is notoriously hard to model, yet predictions for later this century are basically unanimous: unprecedented droughts nearly everywhere food is today produced. By , without dramatic reductions in emissions, southern Europe will be in permanent extreme drought, much worse than the American dust bowl ever was. The same will be true in Iraq and Syria and much of the rest of the Middle East; some of the most densely populated parts of Australia, Africa, and South America; and the breadbasket regions of China.

Remember, we do not live in a world without hunger as it is. Far from it: Most estimates put the number of undernourished at million globally. What happens when the bubonic ice melts? Rock, in the right spot, is a record of planetary history, eras as long as millions of years flattened by the forces of geological time into strata with amplitudes of just inches, or just an inch, or even less. Ice works that way, too, as a climate ledger, but it is also frozen history, some of which can be reanimated when unfrozen.

There are now, trapped in Arctic ice, diseases that have not circulated in the air for millions of years — in some cases, since before humans were around to encounter them. Which means our immune systems would have no idea how to fight back when those prehistoric plagues emerge from the ice. The Arctic also stores terrifying bugs from more recent times. As the BBC reported in May, scientists suspect smallpox and the bubonic plague are trapped in Siberian ice, too — an abridged history of devastating human sickness, left out like egg salad in the Arctic sun.

But already last year, a boy was killed and 20 others infected by anthrax released when retreating permafrost exposed the frozen carcass of a reindeer killed by the bacteria at least 75 years earlier; 2, present-day reindeer were infected, too, carrying and spreading the disease beyond the tundra. What concerns epidemiologists more than ancient diseases are existing scourges relocated, rewired, or even re-evolved by warming.

The first effect is geographical. Before the early-modern period, when adventuring sailboats accelerated the mixing of peoples and their bugs, human provinciality was a guard against pandemic.

But as the tropics creep northward and mosquitoes migrate with them, you will. As it happens, Zika may also be a good model of the second worrying effect — disease mutation.

But there are things we do know for sure about how climate affects some diseases: Malaria, for instance, thrives in hotter regions not just because the mosquitoes that carry it do, too, but because for every degree increase in temperature, the parasite reproduces ten times faster.

Which is one reason that the World Bank estimates that by , 5. We are in a Climate Emergency, but there is still time to avert disaster if we take bold, immediate action at the speed and scale necessary — beyond what politicians have deemed politically possible.

The Deadline and Lifeline on the Climate Clock tell us what we need to do, by when. They are arguably the most important numbers in the world. We offer the ClimateClock to the worldwide climate movement as an internationally coordinated, participatory project.

Between and today, we have witnessed colonization and the Industrial Revolution, the birth of modern states, identities and institutions, the mass combustion of fossil fuels and the associated rise in global temperatures. If we fail to halt climate warming, the next years and beyond will change the Earth in ways that challenge our ability to maintain many essentials for survival — particularly in the historically and geographically rooted cultures that give us meaning and identity.

The Earth of our high-end projections is alien to humans. The choice we face is to urgently reduce emissions, while continuing to adapt to the warming we cannot escape as a result of emissions up to now, or begin to consider life on an Earth very different to this one.

Book talk: "Exponential: how accelerating technology is leaving us behind and what to do about it" with Azeem Azhar — Oxford, Oxfordshire. Edition: Available editions United Kingdom. Become an author Sign up as a reader Sign in.