Chances are you've already heard about how we need to limit global warming to a maximum of 2 degrees Celsius, ideally staying even below 1.5 degrees of warming compared to pre-industrial temperatures. That's what the international community agreed upon during the 2015 climate conference in Paris. But why is it exactly this temperature? And how would 0.5 degrees make much of a difference? To be able to understand this, we will first briefly look at historical CO₂ concentrations to see how extraordinary our current situation is. Afterwards, we are going to discuss the difference half a degree of global warming can make, especially when considering so-called 'tipping points' of the Earth System's climate. We will then touch on different scenarios for the future – one pleasant, the other less so – to better understand what is currently at stake. Finally, we will discuss different strategies to fight climate change, assessing their effectivity and how we might combine them. By the end of this article, therefore, we will have broadened our understanding of climate change. We will understand why broad change is necessary and how it might look. What's more, we will see that this situation offers a unique opportunity to rethink some of our priorities and create a better future in the process. Let's take a closer look.

Historical concentrations CO₂

To be quite frank from the onset: the climate problem we are currently facing is grave. Humanity risks losing the very conditions that enabled our rise as a species. This rise was made possible by the mild climate conditions of the Holocene, the geological epoch that began after the last ice age, about 11,700 years ago. Already, geologists suggest that we have moved out of the Holocene and into the Anthropocene, an epoch characterised by significant human impact on the planets' ecological and geophysical systems. If we look at the long-term atmospheric CO₂ concentration over the most recent 800,000 years, we can see how extreme our current situation is: Throughout the displayed timespan (and beyond it), there have been cyclical periods of temperatures expanding and retreating, with CO₂ levels dropping and rising accordingly (depicted Pleistocene epoch below). The onset of the Holocene coincides with the latest glacial retreat (see the corresponding arrow). There exist different suggestions for when the Anthropocene should begin, among them the onset of the Industrial Revolution in the 18th century or the Great Acceleration after the Second World War. Regardless of such details, the fact of the matter is that humanity has raised atmospheric CO₂ concentrations by an astonishing degree and well beyond otherwise occurring levels. According to recent research, this will postpone the next glacial expansion by at least 50,000 years¹ – an astonishing testament to how massively we now influence the fate of the planet.

But apart from postponing an ice age, the elevated atmospheric CO₂ concentration might permanently catapult us out of the Holocene's comfortable conditions. This is because we are heating up the planet too rapidly and strongly for us – or most other species – to be able to adapt to the new conditions. The rising temperatures pose a massive threat to the stability of the Earth System and our civilisation. But how so?

Shaping our future – one way or another

Perhaps most dauntingly, there's the issue of so-called 'feedback loops' which work as vicious cycles. One example would be the loss of ice surfaces: Ice surfaces reflect sunlight much better than other surfaces, thereby redirecting a portion of the sun's energy back into space. As the planet's ice cover melts because of global warming, earth's reflective capacity diminishes and global warming thus accelerates, in turn compounding the loss of ice surfaces. Another example are be the large quantities of organic matter stored in permafrost soil: As temperatures increase and the previously frozen soil thaws, bacteria begin digesting the large quantities of organic matter it contains. In the process, they release considerable amounts of greenhouse gases into the atmosphere, which in turn further contribute to the global temperature increase.

There's a long list of interrelated feedback loops, and current research suggests that their activation might cause rapid, cascading changes once critical tipping points are reached. In conjunction, these might bring us to a ‘planetary threshold' beyond which we can no longer control, let alone reverse, the Earth System's heating. This dynamic, often termed ‘runaway climate change', could potentially leave us with a barely inhabitable 'Hothouse Earth'. Considering these prospects, it's important to remember that there exists uncertainty about when such tipping points might be reached. It is estimated that runaway climate change could happen around 2 degrees of warming. However, there’s no guarantee that it won’t happen sooner. Therefore, even with only the emissions we assume to cause between 1.5 to 2 degrees of global warming by the end of the century, there is a chance that we might trigger cascades that would irreversibly catapult us out of the manageable range and instead lock us onto the Hothouse Earth path.2 With the current 1.1 degrees of global warming, tipping points of the cryosphere (the entirety of frozen water on the planet, here chiefly the polar ice sheets) might already have been reached, "[committing] future generations to living with sea level rises of around 10 m over thousands of years".³

There are other reasons for aiming for no more than 1.5 degrees of warming, too: While some consequences of the global heating worsen at scale (e.g. extreme weather events like heat waves and storms), there are changes that are disproportionately worse at 2 degrees than they would be at 1.5 degrees. For example, tropical coral reefs' limited chance of recovery would entirely vanish at the 2 degrees mark, and water scarcity in the Mediterranean – already a concern today – would almost double compared to the situation projected for the 1.5 degree scenario. Similarly, crop yields would decrease significantly. This is also because a yearly average increase of 0.5 degrees globally can mean more dramatic seasonal increases in individual regions, ranging between as much as 5–10 degrees.⁴

What we should take away from these findings is that – as a species – we are currently walking along the figurative edge of a cliff that we can't clearly see. In light of the considerable risks we are facing, we would be well advised to steer clear of them as far as possible. Towards that end, aiming for no more than 1.5 degrees of global warming is a very sensible goal. Admittedly, this is increasingly hard to accomplish given our current level of GHG emissions and the reduction commitments in place. It is, however, still possible if we take urgent systemic climate action now. In contrast, if we realised only the current commitments, this would mean at least 3 degrees of warming.³

To illustrate what's at stake, Christiana Figueres and Tom Rivett-Carnac, both former members of the UNFCCC secretariat, wrote a book comparing humanity's possible futures with and without swift and effective climate action. They present us with the choice between a world worth fighting for and the end of human civilisation as we know it. (If you feel like catching a glimpse, check out their articles on the utopian and the dystopian futures.)

Strategies for meaningful action

What we need is no less than a fundamental change in our relationship with the planet, becoming stewards that help stabilise the climate instead of pushing it ever further towards the brink.² This requires lessening our collective impact on the planet, thereby fostering its capability to stabilise the geophysical and biological systems we depend upon. So what strategies are around to achieve this? Sustainability Science offers three fundamental strategies; they are efficiency, consistency, and suffiency. Let's have a look at each of them in turn.

Efficiency is probably the most common strategy. It aims at reducing the cost – monetary or other – of a product or service by making it more resource efficient. This is a principle that's already widely applied, and apart from money it can save a lot of natural resources and energy (consider e.g. all kinds of continually optimised industrial processes, LED lightbulbs, cars using less fuel etc.). Efficiency is an intrinsic goal for most companies because it can increase their competitiveness. That's also why efficiency gains do not automatically benefit the environment. Instead of producing or consuming less, companies and consumers tend to increase their sales and consumption, respectively. A more fuel-efficient car often makes us drive more, and we might care less about switching off the light when our lightbulbs are more energy efficient. This undoing of efficiency-related resource savings is commonly known as the 'rebound effect' and it continues to eat up a lot of our efficiency gains. That of course doesn't mean efficiency shouldn't be pursued. It just means that it can't be our sole answer to the climate crisis.

Consistency may be the least familiar-sounding concept of the three, but it simply boils down to the notion of a circular economy in which natural resources can be reused many times without degrading in quality. A fully consistent economy would be one that has perfected recycling, thereby eliminating waste and the need for virgin non-regenerative natural resources (e.g ores, minerals). Unfortunately, we are quite far from this goal as much of our waste is incinerated, deposited in landfill or – if it is recycled – 'downcycled'. This means that the resources' quality decreases and that they can no longer be used in all products (e.g. not for food-grade packaging or high-performance materials). Historically, materials have often been selected and combined for performance and convenience, rather than for recyclability. Because of this, recycling processes are complex, limited, and therefore frequently financially impractical. With ever-increasing global demand, sustainable resource use therefore stays out of reach. What's more, even perfect consistency doesn't eliminate the production processes' energy consumption. That’s a problem because the amount of renewable energy we can continually produce is limited. Much as with efficiency, consistency can therefore only be a partial solution.

Nonetheless, many mainstream economists claim that advancements in efficiency and consistency will enable us to ‘decouple' economic growth from climate change (and other planetary degradation). This is also frequently referred to as 'green growth'. Unfortunately, there exists no empirical evidence supporting the claim that green growth at the required scale is happening or could happen in the future.⁵

This is where sufficiency comes into play. Unless we resort to wishful thinking, it's hard to imagine a sustainable future without ourselves becoming more modest consumers, which means requiring less natural resources and energy. This, in turn, would require less production. Sufficiency therefore means finding a state of 'enough' – individually and as a society – that satisfies our material needs and enables living within the boundaries of what the planet can continuously provide. It means slowing down the 'metabolism' of humanity as a whole.⁶

More often than not, this is framed as a loss to our individual quality of life and equated with backwardness and a lack of resources. However, it does not have to be this way. There's an ever-increasing number of people pursuing a different kind of work-life balance, moving away from material wealth towards more personal fulfilment. This could mean spending more time with family and friends, taking care of kids or relatives, focussing on hobbies or doing voluntary work. While we might end up owning, shopping and flying less, we would have the time to lead richer, healthier, more social everyday lives with less stress and more inspiration. Right now, such a sufficient lifestyle is at odds with our economic model, but who is to say that we won't shift the yardstick of societal success away from GDP (which even increases when a fatal car crash happens) and towards measures such as equity, quality of life, and needs met within a society.⁷

Of course, this kind of society has not yet arrived, and it will certainly not arrive automatically. It requires personal and societal shifts that in term require political engagement. Far too often, we tend to forget that society is made by and for us. In this vein, political engagement means taking matters in our own hands. It means encouraging each other. It means coming together and demanding change from politics and companies. It means envisioning a shared positive future and bringing it about. At eco.income, we think that tackling our personal climate impact is a perfect starting point towards a society of sufficiency and happiness that thrives within the boundaries of the planet. Even if we feel like our individual actions don't make a difference, we shouldn't underestimate how much change each of us can inspire among our peers. In the age of social media, this is more true than ever. So instead of getting paralysed by the challenge climate change poses, let's make our move towards a desirable future.

Footnotes

1. PIK (2016): Human-made climate change suppresses the next ice age.
2. Steffen et al. (2018): Trajectories of the Earth System in the Anthropocene.
3. Lenton et al. (2019): Climate tipping points – too risky to bet against.
4. NASA (2016): Why a half-degree temperature rise is a big deal.
5. EEB (2019): Decoupling debunked – Evidence and arguments against green growth as a sole strategy for sustainability.
6. In fact, low and middle income countries will require further growth to enable dignified, happy lives for their inhabitants while industrialised economies overwhelmingly don't. The goal, therefore, is to become growth agnostic. This means growing when needed instead of needing to grow constantly.
7. Kate Raworth paints an inspiring picture of what this could look like with her Doughnut Economics. Watch Raworth sum up the fundamentals in her 2018 TED Talk.