Is net zero sustainable?

Net zero commentary focuses principally on whether it is achievable, and if so, by when^*.  A distinct question asks whether the goal will be sustainable, whatever the date reached.

Climate is one phenomenon within the biosphere (the regions of our planet occupied by living organisms in the air, land and sea). It varies over time and geography. Another marvel is biodiversity (the variability among living organisms). Like climate, biodiversity fluctuates over space and time. Europe (area 1 billion hectares) has 570 known butterfly species – the Manu National Park in Peru (just 1.7 million hectares), has 1,300. Today, tropical rainforests, the oldest major terrestrial vegetation, cover around 6% of the earth’s land surface. In the deep past of the dinosaur era, these woodland wonders blanketed nearly all of the then supercontinents.

Looked at holistically, a complex, changing network links all life across the globe and through the generations. Examining climate or biodiversity in isolation risks missing the wood for the trees. Sustainability involves ensuring the integrity of the connections within the biosphere, despite its uncertainties and changing nature.

As we look to secure the future, a human population of over eight billion will play a pivotal role – potentially for good or bad.

The bad news is that we should expect increases in atmospheric carbon and rising global temperatures to increase biodiversity loss, in turn further increasing global warming. For example, human influence on biodiversity today comes principally via deforestation and intensive agricultural practices, together with the exploitation of marine ecosystems. As a result, the earth’s natural carbon sink is weakened, as biodiversity naturally helps to store carbon on the land and in the oceans.

Moreover, ecosystems tend to decline rapidly after a threshold is breached (around 20% degradation). Of course, plants and animals attempt to resist and adapt to ecosystem challenges, but, in the end, they face existential threats. Thus, biodiversity impairment can lead to another phenomenon within complex systems – a tipping point – a moment of ecosystem collapse, or worse, sets of tipping points creating cascades of extinctions. Our best estimates suggest that extinction rates in the recent past are running at 100 or more times faster than in pre-human levels (The Royal Society).

The good news is that nature is there to help us, honed through billions of years of evolution. Nature-based solutions (NBS) can help to thwart both the biodiversity and climate threats, and much more besides, including improving human health. Care for nature is the easiest win:win for the systemic challenges we face in the biosphere, creating virtuous cycles between climate, biodiversity and well-being, for example. Indeed, NBS are what the philosopher Nassim Nicholas Taleb might call ‘anti-fragile’ solutions, allowing the system (in this case, the biosphere) to bounce back stronger from shocks, human-induced or otherwise.

So, how should we draw on the intelligence of nature? We all benefit from a better biosphere, as will our descendants, suggesting a ‘free rider’ problem (you pay - I benefit), in turn creating a potentially important role for government policy.

Yet this simple instinct comes with a health warning – there is no easy alignment of climate and nature policies, with difficult trade-offs inevitable. Individual policies imply different co-benefits and operate over different timescales, from immediate to centuries. Moreover, failure to see the big picture can mean that the wrong policies in one part of the system can lead to greater problems elsewhere.

Subsidies are one common narrowly focused policy tool. Lobbyists love them. Yet, the greatest thing that governments worldwide could do right now is to reel in those in agriculture and fossil fuels that are contributing to biosphere problems in the first place.

A better place to start is to protect rigorously what we have left in nature. The UK Environment Act (2021) aims to do this, creating legally binding targets to protect our environment, including “halting the decline in species by 2030” together with longer-term targets for restoration of biodiversity, air and water quality. It is part of a much wider set of UN Global Biodiversity Targets to protect 30% of global land and oceans by 2030.

However, laws need detailed delivery plans and enforcement. In the UK’s case, the Chair of the Office for Environmental Protection was recently quoted in the Guardian: “If action is not taken, England will fail to meet its goal of halting nature’s decline by 2030, as well as a host of other vital nature targets.” That is not reassuring, despite government protestations to the contrary. Ultimately, a government in breach of its own laws may end up in court. Perhaps more potently, political embarrassment may encourage the right action.

Overall, the preliminary UK report is that we must do better. No attention to nature implies no sustainable net zero. On the contrary, it means the approach of an evolutionary dead end.

^* Chris Goodall, Possible – Ways to Net Zero (Profile Books, 2024) will present his ideas on this topic at an Investec seminar chaired by me on 6 June. Please contact your Investec representative, or send me a direct message on LinkedIn, if you would like to attend.