It is inspiring to see the world mobilise around the global vision of the 17 UN Sustainable Development Goals (SDGs) to end poverty and hunger, ensure sustainable water access for all, fight inequalities, tackle climate change, and more. Local governments, companies, and civil society are developing plans for how they can contribute to achieving them. But a key piece is missing – clear targets for maintaining Earth’s life-support systems, the global commons.
Four of the goals focus directly on Earth’s life-support systems – on water, climate, oceans, and land – but only one of them has a clear target based on scientific research. SDG 13, which seeks to “combat climate change and its impacts” has adopted the same target that 197 nations agreed to in the Paris agreement – to keep global average temperature rise to well below 2C above pre-industrial levels.
This target may not be perfect, but it has been vital for advancing progress in addressing the climate crisis. It works because it is grounded in science and is quantifiable, simple to communicate, and within the realms of political reality. Many businesses have now adopted climate goals that translate it into targets that work for them, most prominently through the “science-based targets” developed by World Resources Institute, CDP (formerly the Carbon Disclosure Project), World Wildlife Fund, We Mean Business, and other groups.
We do not yet have science-based targets for the other vital components of Earth’s life-support systems, like water, oceans, and land. Most of the SDG targets focused on Earth systems are vague and not actionable. They include, for example, calls to “minimise and address the impact of ocean acidification,” or to “restore degraded forests and substantially increase afforestation and reforestation globally”.
As with any business or policy decisions, implementing the SDGs will involve tradeoffs. If decision-makers are effectively to evaluate these trade-offs, they will need to understand potential boundaries – similar to 2C for climate – beyond which our natural life-support systems may break down.
Can we develop science-based targets for other parts of Earth’s life-support systems? One place to start is the nine planetary boundaries – including, for example, the diversity of life on Earth, freshwater, and air pollution. Identified by scientists in 2009, they are a set of limits that define what makes a “safe operating space for humanity”. Researchers refined this concept further in 2015, but much work remains to be done. We don’t yet have precise numbers for all of these boundaries and significant uncertainties remain even among those that have been quantified.
Some argue that boundaries relating to soil or plastic pollution, for example, are missing. Others say that the boundaries framework may not work at a global scale for some natural systems, and others may be difficult to apply at local, national or regional levels. All these valid and important issues must be confronted in a search to identify what the limits are for maintaining our planet in a safe operating space.
The good news is that the international scientific community – much of it working through Future Earth’s global research projects – has been analysing these Earth systems for decades. What is now needed is to assess all that existing knowledge and put it to work in developing a holistic suite of science-based targets – ones, critically, that could be used by any nation, city, or company.
This is a bold and ambitious effort, but it’s necessary to realise the vision of the SDGs. To be successful, we will need to consider three principles:
1. The initiative must draw from the best science from all regions of the world.
2. While the targets must be science-based, they must also be shaped through dialogue between scientists and policymakers – with strong engagement from both the global north and south – if they are to be operational.
3. They must be quantifiable and applicable at multiple scales.
We must start soon. Science is a slow process, and ideas take time to cross from academia into society and policy. But we do not have the luxury of time. The world needs to act fast. Without these science-based Earth targets, we cannot fully achieve the ambitious vision of the SDGs. And, perhaps more importantly, without them we may unwittingly cross into an unsafe operating space for humanity.