Mark Lynas is a British journalist who focuses on climate change. He’s been on a world tour, documenting impacts of climate change. Armed with photos that give clues to the impacts of climate change, he introduces us to some possible climate change scenarios, depending on whether global warming causes one or two degrees of mean temperature rise or five to six.
Lynas’s argument is that we’re at a unique moment in geological time, a moment where the geological era is defined by human impact, rather than natural factors. He argues that this can’t be a moment where people are on different sides: “it’s all of us versus the biosphere.”
Lynas grew up in Peru, and returned to the glaciers outside Lima to recreate a photo his father had taken 20 years later. The photos side by side are astounding – a tongue of glacier almost a kilometer long has disappeared in those two decades. Those glaciers feed rivers that supply Lima – the second largest desert city in the world – with water. It’s not hard to imagine what too little water might mean to the 7 million people who live there.
Tuvalu’s Ministry of Environment
Too much water can be at least as devestating. Tuvalu is a nation on a coral atoll, which is rapidly dissapearing into a sea. Seawalls won’t help, as the rock Tuvalu is built on is pourous. As sea levels rise – as they are already doing – the Tuvalu government is working to move residents to New Zealand. This is, perhaps, the first geographical extinction of a nation.
Lynas gives us a tour of possible futures, organized by possible rises in temperature – he refers to them as code blue through code red, poking fun at the American terror warning system:
A one degree change in temperature – already inevitable – we’ll see most coral reefs die, and may see the American great plains return to desert
A two defree change – which we might be able to accomplish if we capped global warming very soon – we’ll see a major biodiversity crisis.
At three degrees, the Greenland ice sheet melts and we see a 6 meter seawater rise – which eliminates much of Florida, Manhattan and a good chunk of the Eastern seaboard of the US… and that’s just in one country. It’s also likely to chage how rainforests work – they’re likely to die and burn, which will release huge amounts of carbon into the atmosphere.
At four degrees, the Artic ice sheet melts, and polar ecosystems dissapear.
At five degrees – code red – most glaciers are gone, which means whole parts of the world – Pakistan, for instance, which relies on runoff from the Hindu Kush glaciers – will be uninhabitable. We’ll have less land from sea rise, and only a fraction of what remains will be habitable.
Lynas tells us he can’t offer probabilities for these five scenarios – or a more extreme one with a six degree rise. But it’s clear that any of these scenarios requires reacting to global warming as a major priority for world governments, not a subject we’re unwilling to tackle.