It is into this intricate relationship that humanity has stormed, adding enough warming gases to the atmosphere to shift the delicate equilibrium of the past millennia and change global climate for centuries to come.
The atmosphere acts as a blanket against the unimaginably cold temperatures of outer space, and the main gas responsible for these cosy conditions is carbon dioxide. Carbon dioxide is invisible because sunlight passes straight through the molecule. However, it is opaque to the infrared rays that heat travels in, so, like the glass in a greenhouse, it warms the air. Sunlight travels unhindered through the atmosphere until it hits the surface of the Earth. If that surface is very reflective – like a shiny white glacier – then most of the rays will bounce straight back as light. But if the surface is dark – like black rock, soil or ocean – then this energy is absorbed as heat, which radiates into the atmosphere as infrared rays that can’t pass through the carbon dioxide. In this way, heat gets trapped bouncing between the atmosphere and the Earth, warming them both and sustaining life.
We know from fossil records that the planet’s climate has swung between tropical prolificacy that saw metre-long insects, and ice ages that killed off the majority of life forms. These catastrophic big freezes were the result of massive events like meteor hits or supervolcano eruptions that filled the atmosphere with so much dust that sunlight couldn’t penetrate to the planet and killed the animals that produce that all-important carbon dioxide. At such times, the concentration of carbon dioxide in the atmosphere dropped as low as 160 parts per million (ppm) molecules.
For the past half a million years – the world into which humans evolved – the carbon dioxide concentration has hovered between 200 ppm (during ice ages) and the comfortable 280 ppm of the Holocene. Historically, the main fuel humans used was wood, emitting the same amount of carbon dioxide that the tree absorbed during its growth. But in the Anthropocene, the vast majority of our energy comes from burning fossil fuels – emitting the huge stores of carbon dioxide from plants and creatures that died millions of years ago. As I write this, carbon dioxide concentrations in the atmosphere are 40% higher than pre-industrial levels – 400 ppm – the atmosphere is warmer, more energetic and holds more water, giving rise to more extreme weather. Scientists are saying that there is no longer such thing as ‘normal climate’, by which they mean what was normal for the Holocene.
We are also using the atmosphere as a repository for other gases released during combustion and for a range of other pollutants, including refrigerants that attack the ozone layer high in the stratosphere that protects us from UV rays.
And, in the Anthropocene, the atmosphere has also become humanity’s global voice. Just as visible light can travel through the air, so can sound, radio waves, and microwaves, enabling instant communication by radio, telephone and Internet. The atmosphere is as transparent to the human-generated pulses in the satellites it hosts as it is to the sun’s vital energy, and allows our species to traverse the globe virtually in seconds.
In 1932, King George V became the first monarch to deliver a Christmas Day message by radio to 20 million listeners from Britain to the outposts of the empire. In a script written for him by Rudyard Kipling, he addressed ‘men and women so cut off by the snows, the deserts, or the sea, that only the voices out of the air can reach them’. The atmosphere of the Anthropocene is now full of these ‘voices out of the air’. Imagine if we could see the beams emitted by our radios, laptops, televisions, mobile phones and other devices. For almost all of the planet’s 4.5 billion-year history, the atmosphere has been lit solely by extraterrestrial flares, like suns or meteors, or by electrical storms. Now, the skies are infused with artificial lights of different wavelengths as our devices communicate with each other and with us. And that’s just in the invisible spectrum. In the visible spectrum we have lit up our world so brightly that towns and cities can be seen from space at night and, for city dwellers, the stars fade into oblivion.
Satellites enable us to look down from space at our home as no eye has done before. The same cameras show us in unprecedented detail just how much we are changing our world. Using the Internet, we can pool our shared knowledge and intellectual resources to solve new problems, to cooperate in different ways and to transcend the geography of our planet to inhabit a virtual room no matter where we are physically.
The atmosphere has also become a playground for our aerial adventures, a medium for rapid and direct long-distance travel around and beyond our planet into space. Humans can now journey from London to Sydney in less than a day. We can trade between communities within time frames that allow fresh blueberries to be picked by a human in South Africa and eaten by another hours later in London.
Our technological invasion of the skies has allowed us to communicate across our species in a way that no other life form has. The atmosphere is un-ownable, common to all Earth-dwellers – it gives life with the first breath and life is extinguished with the last. In this chapter I look at how our changes to the atmosphere will help decide how societies develop over the coming decades.
I meet Mahabir Pun outside the tiny airstrip in Pokhara, some 200 kilometres west of Nepal’s capital Kathmandu. He is a shortish fellow in his mid-fifties with an inflatable ball of a stomach and thick black hair that emerges at extraordinary angles above his square face.
‘Gaia, come. Come!’ he says urgently, setting off ahead of me at a rapid pace and agitating his hair further, so that it stands wildly up on one side.
As I trot along behind him, people gather to watch the unusual spectacle of the pale, sweating foreign woman dressed for Arctic exploration with a bulging backpack following a local guy in light cottons and open sandals.
A political demonstration earlier in the week has led the Maoist government to impose a military-enforced curfew in the area, banning all vehicles including motorbikes, buses and taxis, so Mahabir has had to walk several kilometres to meet me. But here, as in every other place that lacks functional governance, people are resourceful. Casting a sly look around, Mahabir motions for me to get on one of two motorbike taxis, while he takes the other, and we speed off.
Pokhara is a lake town, shimmering within a halo of mountains. It is closest of anywhere in Nepal to achieving the new prime minister’s promise of turning the country into the ‘Switzerland of Asia’. Enticing cafés and shops crowd the lanes beside the lake. Brightly clad clusters of men, women and youngsters gather at a little jetty that delivers worshippers to the pretty Buddhist temple on an island a hundred metres away. Women wearing saris are knee-deep in the lake dousing rainbows of laundry and shampooing their long black hair. Fish leap clear of the surface and birds circle overhead looking for snacks.
Rising above the town is the oddly shaped peak of Fishtail Mountain, whose sheer granite sides point a geological finger into the blue sky. It is mid-December in the Himalayas, there should be ice on this lake and snow descending far down the mountainsides. But only the highest peaks are white; pink flowers bob at head height on green stalks that sway in the sun. We stop and I remove another fleece.
The picture-postcard prettiness includes some less appealing details, I begin to notice. A fetid slick of vibrant green run-off from the town’s cafés and businesses is discharging raw sewage and some sort of oily pollutant directly into the lake. Dirty, poorly clad children are poring over discarded plastic and other solid waste littering the banks – while I watch, one boy walks a few metres away, pulls down his shorts and defecates at the lake’s edge. Looking upwards, I see that the quaint country homes lining the street are in fact filthy dilapidated mud-floored shacks, offering little protection or comfort for their large families. We’re a long way from Switzerland here. And this is one of the most improved parts of the country.
In trying to grasp the enormity of the development task facing the poor world at the beginning of Anthropocene, Nepal is a good place to start. Sandwiched politically, culturally and geographically between two of the world’s fastest emerging economies, Nepal has avoided following either the Chinese or Indian model for national growth and slid further into decline. It is one of the ten poorest countries, with more than one-third of the population living below the poverty