How long is climate

Whether it's the evidence of heatwaves, or the influence of Swedish school striker Greta Thunberg, or the rise of Extinction Rebellion, there has been a marked change in public interest in stories about climate change and a hunger for solutions that people can put in place in their own lives. People are demanding significant action, and politicians in many countries have woken up to these changes.

Ideas like the green new deal in the US , which might have seemed unfeasible a few years ago have gained real traction. Some countries like the UK have gone even further and legislated for net zero emissions by , the long-term goal that will keep temperatures down. Prince Charles' sense that the next 18 months are critical is shared by some climate negotiators. But if Donald Trump doesn't prevail in the presidential election that position could change, with a democrat victor likely to reverse the decision.

Either step could have huge consequences for the climate fight. Right now a number of countries seem keen to slow down progress.

Just a few weeks ago in Bonn, further objections from Saudi Arabia meant it was again dropped from the UN negotiations, much to annoyance of small island states and developing nations. There will be significant pressure on the host country to ensure substantial progress. But if there's ongoing political turmoil around Brexit then the government may not have the bandwidth to unpick the multiple global challenges that climate change presents.

But the movement here has barely started to think about how to apply sufficient pressure. At the launch of their review of progress made by the UK government on tackling climate change, the country was found not to be on track despite legislating for net zero emissions by If we don't see that, I fear the government will be embarrassed at COP And it's not all about climate change. While the decisions taken on climate change in the next year or so will be critical, there are a number of other key gatherings on the environment that will shape the nature on preserving species and protecting our oceans in the coming decades.

Earlier this year a major study on the losses being felt across the natural world as result of broader human impacts caused a huge stir among governments. To address this, governments will meet in China next year to try to agree a deal that will protect creatures of all types. The Convention on Biological Diversity is the UN body tasked with putting together a plan to protect nature up to Nations pulled together to defeat the pandemic, and that launched a new era of cooperation to prevent a climate disaster.

Investments in green energy and new technology yielded rapid cuts in emissions of carbon dioxide, putting the world on track to limit global warming to around 1. Or maybe not. In , the world could look back and see the pandemic as little more than a blip in a long and mostly futile effort to stave off global warming.

Despite a temporary drop in carbon emissions from the outbreak, countries turned to cheap fossil fuels to revive their economies after the crisis.

These are just two possible visions of the future. Nobody knows how the current pandemic will play out; nor is it clear whether humanity will ultimately come together to avoid a potential climate catastrophe. But climate researchers need to explore what kinds of problem might emerge with different levels of warming. So they have developed a suite of scenarios intended to represent a range of futures that humanity could face 1.

Their goal is to investigate how different policies might alter carbon emissions — and how the planet will react to all of that heat-trapping gas.

At one end of the spectrum, optimistic scenarios explore worlds in which governments join forces to advance low-carbon technologies while reducing poverty and inequality. The other end sees countries ramp up their use of cheap fossil fuels, pursuing economic growth at all costs. These simulations will inform climate research for years to come, and will play a central part in the next major assessment of global warming by the Intergovernmental Panel on Climate Change IPCC , which is due out next year.

The research could also have a key role in the negotiations around a new set of commitments to reduce emissions under the Paris climate agreement. Source: Adapted from Fig. Model Dev. Critics have charged that this particular scenario, which has had a central role in climate studies for more than a decade, is misleading because it includes unrealistic amounts of coal use — a roughly fivefold increase by But many researchers dismiss that criticism, saying that even such high-emissions scenarios have value as long as people understand their underlying assumptions and limitations.

A massive release of methane from Arctic permafrost, for example, could have a similar effect to huge surges in fossil-fuel use. The scenarios are not designed to project emissions, but to investigate different levels of warming and types of economic development.

They help a wide variety of researchers: climate modellers use them to test their models and project the impact of increasing greenhouse-gas emissions; economists need them to explore the costs of policies; and ecologists rely on them to predict changes to ecosystems around the globe. In April , a group of experts tasked with forecasting potential futures met in Bilthoven, the Netherlands, to prepare for the first IPCC assessment, which was due out the following year.

They created scenarios describing how much carbon dioxide, methane and other heat-trapping gases nations might produce over the next century 3.

And those possible future worlds — from the extremely polluted to the exceptionally clean — provided the raw material for climate modellers to project how the planet might react.

Since then, the IPCC has updated the main emissions scenarios several times. But the situation changed in , when the IPCC decided to get out of the scenario-development business because of pressure from the United States and others who argued that the organization should assess, not guide, science. The group provided a set of four projections of future carbon pollution levels — dubbed Representative Concentration Pathways RCPs — that could be run by climate-modelling groups around the world to produce forecasts about the fate of the planet 5.

The RCPs were selected to portray different levels of radiative forcing — a number that reflects how much extra warming results from greenhouse-gas emissions. That job was left for other researchers, who would later produce sets of emissions trends that could drive greenhouse-gas concentrations in ways that mimic the RCPs.

Moss says the RCPs were designed to capture the spectrum of warming possibilities in the scientific literature and create a significant enough range between the high and low projections that climate modellers would be able to differentiate between them.

Over time, however, the RCPs took on a life of their own. At that concentration, compared to the air we breathe now, human cognitive ability declines by 21 percent. Other stuff in the hotter air is even scarier, with small increases in pollution capable of shortening life spans by ten years.

The warmer the planet gets, the more ozone forms, and by mid-century, Americans will likely suffer a 70 percent increase in unhealthy ozone smog, the National Center for Atmospheric Research has projected. Which does make you think again about the autism epidemic in West Hollywood. Already, more than 10, people die each day from the small particles emitted from fossil-fuel burning; each year, , people die from wildfire smoke, in part because climate change has extended forest-fire season in the U.

By , according to the U. Forest Service , wildfires will be twice as destructive as they are today; in some places, the area burned could grow fivefold. What worries people even more is the effect that would have on emissions, especially when the fires ravage forests arising out of peat. Peatland fires in Indonesia in , for instance, added to the global CO2 release by up to 40 percent, and more burning only means more warming only means more burning.

That is especially bad because the Amazon alone provides 20 percent of our oxygen. Then there are the more familiar forms of pollution. Literally unbreathable. That year, smog was responsible for a third of all deaths in the country. The violence baked into heat. Climatologists are very careful when talking about Syria. They want you to know that while climate change did produce a drought that contributed to civil war, it is not exactly fair to saythat the conflict is the result of warming; next door, for instance, Lebanon suffered the same crop failures.

But researchers like Marshall Burke and Solomon Hsiang have managed to quantify some of the non-obvious relationships between temperature and violence: For every half-degree of warming, they say, societies will see between a 10 and 20 percent increase in the likelihood of armed conflict.

In climate science, nothing is simple, but the arithmetic is harrowing: A planet five degrees warmer would have at least half again as many wars as we do today.

Overall, social conflict could more than double this century. This is one reason that, as nearly every climate scientist I spoke to pointed out, the U. What accounts for the relationship between climate and conflict? Some of it comes down to agriculture and economics; a lot has to do with forced migration, already at a record high, with at least 65 million displaced people wandering the planet right now.

But there is also the simple fact of individual irritability. Heat increases municipal crime rates, and swearing on social media, and the likelihood that a major-league pitcher, coming to the mound after his teammate has been hit by a pitch, will hit an opposing batter in retaliation.

And the arrival of air-conditioning in the developed world, in the middle of the past century, did little to solve the problem of the summer crime wave. Dismal capitalism in a half-poorer world. The murmuring mantra of global neoliberalism, which prevailed between the end of the Cold War and the onset of the Great Recession, is that economic growth would save us from anything and everything. Before fossil fuels, nobody lived better than their parents or grandparents or ancestors from years before, except in the immediate aftermath of a great plague like the Black Death, which allowed the lucky survivors to gobble up the resources liberated by mass graves.

Of course, that onetime injection has a devastating long-term cost: climate change. The most exciting research on the economics of warming has also come from Hsiang and his colleagues, who are not historians of fossil capitalism but who offer some very bleak analysis of their own: Every degree Celsius of warming costs, on average, 1.

This is the sterling work in the field, and their median projection is for a 23 percent loss in per capita earning globally by the end of this century resulting from changes in agriculture, crime, storms, energy, mortality, and labor.

Tracing the shape of the probability curve is even scarier: There is a 12 percent chance that climate change will reduce global output by more than 50 percent by , they say, and a 51 percent chance that it lowers per capita GDP by 20 percent or more by then, unless emissions decline. By comparison, the Great Recession lowered global GDP by about 6 percent, in a onetime shock; Hsiang and his colleagues estimate a one-in-eight chance of an ongoing and irreversible effect by the end of the century that is eight times worse.

The scale of that economic devastation is hard to comprehend, but you can start by imagining what the world would look like today with an economy half as big, which would produce only half as much value, generating only half as much to offer the workers of the world.

It makes the grounding of flights out of heat-stricken Phoenix last month seem like pathetically small economic potatoes. And, among other things, it makes the idea of postponing government action on reducing emissions and relying solely on growth and technology to solve the problem an absurd business calculation. Every round-trip ticket on flights from New York to London, keep in mind, costs the Arctic three more square meters of ice.

Sulfide burps off the skeleton coast. That the sea will become a killer is a given. Barring a radical reduction of emissions, we will see at least four feet of sea-level rise and possibly ten by the end of the century.

At least million people live within ten meters of sea level today. But the drowning of those homelands is just the start. There, the small fish die out, unable to breathe, which means oxygen-eating bacteria thrive, and the feedback loop doubles back. Hydrogen sulfide is so toxic that evolution has trained us to recognize the tiniest, safest traces of it, which is why our noses are so exquisitely skilled at registering flatulence.

Plants, too. It was millions of years before the oceans recovered. Our present eeriness cannot last. Surely this blindness will not last — the world we are about to inhabit will not permit it. Humans used to watch the weather to prophesy the future; going forward, we will see in its wrath the vengeance of the past. You can find it already watching footage of an iceberg collapsing into the sea — a feeling of history happening all at once.

It is. Many people perceive climate change as a sort of moral and economic debt, accumulated since the beginning of the Industrial Revolution and now come due after several centuries — a helpful perspective, in a way, since it is the carbon-burning processes that began in 18th-century England that lit the fuse of everything that followed.

But more than half of the carbon humanity has exhaled into the atmosphere in its entire history has been emitted in just the past three decades; since the end of World War II, the figure is 85 percent.

She has been smoking for 57 of those years, unfiltered. Some of the men who first identified a changing climate and given the generation, those who became famous were men are still alive; a few are even still working. Like most of those who first raised the alarm, he believes that no amount of emissions reduction alone can meaningfully help avoid disaster.

Jim Hansen is another member of this godfather generation. Hansen has recently given up on solving the climate problem with a carbon tax alone, which had been his preferred approach, and has set about calculating the total cost of the additional measure of extracting carbon from the atmosphere.

Hansen began his career studying Venus, which was once a very Earth-like planet with plenty of life-supporting water before runaway climate change rapidly transformed it into an arid and uninhabitable sphere enveloped in an unbreathable gas; he switched to studying our planet by 30, wondering why he should be squinting across the solar system to explore rapid environmental change when he could see it all around him on the planet he was standing on.

The answer, they suggested, is that the natural life span of a civilization may be only several thousand years, and the life span of an industrial civilization perhaps only several hundred. In a universe that is many billions of years old, with star systems separated as much by time as by space, civilizations might emerge and develop and burn themselves up simply too fast to ever find one another.