Science, Certainty, and Climate Action

My earlier post about methane highlighted some areas of tension in interpretations of the science of global heating. This is just one arena where perspectives on science can be polarising. The COVID pandemic also comes to mind. This post is an attempt to clarify what we mean by science, certainty, and evidence in climate and land-use debates. It is not a rejection of science, but an argument for taking science seriously, while mindful of its limits, its uncertainties, and its susceptibility to distortion.

The stakes are high as we navigate this existential crisis. Why does so much climate debate treat uncertain science as settled truth, and why does that matter for real-world solutions?

The continuum of certainty

Some science is settled – if I were to jump off a step 100 times, I am sure that every time gravity will move me down toward the ground. This is grounded truth. At the beginning of the continuum is a hypothesis. When Sir Isaac Newton watched an apple fall, he formulated a hypothesis about gravity.

Here is a continuum of five stages of scientific certainty with examples. Disagreement often arises not because people reject science, but because they treat different points on this continuum as equally certain.

1. A hypothesis is a plausible explanation for some phenomenon. For example, Equilibrium Climate Sensitivity (ECS) is the estimated long-term global temperature increase from a doubling of atmospheric CO₂. It is foundational to climate projections and carbon budgets, yet it remains uncertain even after decades of research, largely due to the complexity of Earth systems.
2. A model is a calculated approximation of a phenomenon. Global GHG inventories are an example. CO₂ models are broadly accepted, while the most abundant GHG, water vapour, which remains difficult to model accurately at scale.
3. An empirical correlation based on observed relationships is more certain. For example, we know that increasing soil carbon by a percentage point will increase water retention.
4. Our mechanistic or observed understandings of known processes reveal the dynamics of, for example, photosynthesis.
5. Grounded truth provides certainty and a solid foundation for action. I have previously presented evidence for the cooling effects of vegetation. This is partially grounded in the phenomenon of the urban heat island effect and I was able to verify this using an infrared lens to contrast the difference between constructed or bare surfaces with vegetation.

Given the high stakes, climate action grounded in observed reality is likely to be more robust than action based primarily on modelling. For example, reducing fossil fuel use correlates directly with reduced CO₂ emissions, while mechanisms such as emissions trading schemes are based on modelling and market dynamics. In Aotearoa, this has contributed to the proliferation of monocultural pine plantations.

Having taught soil science and botany, I am acutely aware of the gap between what can be modelled and what is only understood by long observation of living systems.

Diverse world views

Good scientists range across the continuum of certainty often moving between them. And one of the greatest, Albert Einstein, also generated insights through intuition.

It may also be helpful to be explicit about where I am coming from. I have taught soil science and botany and my professional life has been shaped by working closely with living systems rather than abstract ones alone. I am also a member of the Bahá’í Faith, which holds as a core principle that science and religion must be in harmony. This does not mean elevating belief above evidence. On the contrary, it insists that science be pursued with humility, and that ethical frameworks remain responsive to evidence rather than ideology. In the context of climate and land-use debates, this perspective makes me wary of both anti-scientific thinking and of treating provisional scientific models as settled truth.

For me, knowledge becomes more grounded when I can triangulate with these two perspectives. This pursuit of harmony resonates strongly with systems science and ecology, where wholes cannot be understood by dismantling them into parts alone.

And living and working with Māori, I have developed an appreciation for a more holistic and connected indigenous worldview.

Distorting science

In his book The Structure of Scientific Revolutions, Thomas Kuhn introduced the concept of scientific paradigms. He contended that, rather than advancing in a linear progression, science moved from one established paradigm to another. The new paradigm was often vigorously resisted by the orthodoxy but eventually prevailed to become settled science. An example is the paradigm shift from Newton’s clockwork view of the universe to Einstein’s relativism.

Paradigms are productive in that they organise knowledge but eventually become supplanted by a more cohesive and grounded knowledge. Kuhn’s insight was not that science is untrustworthy, but that it is human, shaped by institutions, incentives, and dominant ways of seeing. He permanently challenged the idea of complete objectivity.

In the context of global heating, I welcome the shift from the GHG paradigm to an Earth systems paradigm, where the complex interactions of Earth systems and solar energy are more completely understood. This shift will support a broader array of climate solutions.

Science is also distorted when research funding, policy targets, and commercial interests align too tightly. Some questions are asked repeatedly, while others are rarely asked at all.

Food production and science

From the narrow boundary GHG perspective, food production is problematic. A shift to a broader systems perspective repositions food production as an arena for developing climate solutions. When I first studied horticulture the primacy of N, P and K was emphasised. Over time, a much more nuanced and complex understanding of plant nutrition has emerged that generates cascades of benefits for the climate, the environment and human health when put into practice. Agriculture illustrates the problem clearly, but it is not unique. The same reductionist tendencies appear in energy, biodiversity, and water policy.

Adapt or maladapt?

As with other epistemologies, science is embedded in human cultures. Edgar Schein defined culture as:

… a pattern of shared basic assumptions learned by a group as it solved its problems of external adaptation and internal integration, which has worked well enough to be considered valid and therefore taught to new members as the correct way to perceive, think, and feel. From Organizational Culture and Leadership, Edgar Schein.

Our climate responses are not just technical, they are cultural too. We have a massive problem to solve and part of our internal integration will be how we make sense of our world using all appropriate tools at our disposal. If we get this right, we adapt; if not, we maladaptwith significant consequences for those who come after us.

In reflecting on the themes of this post it would be hypocritical of me to stand in my own sense of objectivity, so I welcome your feedback and perspectives.

I am grateful for editorial feedback from an AI language model, which helped me clarify structure and tone. Responsibility for the views expressed remains entirely my own.