Katherine Richardson: The loss of biodiversity worries me in a way more than the climate crisis

It is not every day that a poetry reading gives me goosebumps, but on a research trip in June - on an otherwise very turbulent Irminger Sea off East Greenland - one of my younger colleagues read one of his own poems, and it hit me right in solar plexus.

It was not the subject of the poem, but rather my colleague's technique that captured the emotions. At the beginning of the poem, she used all the letters of the alphabet, but during her writing process, she removed letters and forced herself to use only words that contained the remaining letters.

When the letters first began to disappear, the text was fully understandable, although the language obviously became somewhat poorer. But the further into the poem she came, the less meaning the text gave. Eventually the words disappeared and only a few incomprehensible sounds remained.

The author explained that the alphabet in her worldview represented the diversity of life, what we call biodiversity, and that one should think of the individual letters as different species. Once the letters are assembled, they have an obvious function in the form of language. When the letters start to disappear, the function is degraded but still performed. But when a sufficient number disappears, the letters lose the ability to form a language.

The reason why the poem hit me so hard is that I am convinced that she is right: one can well consider biodiversity and the function it performs in the Earth's orbit, in exactly that way.

Our problem is that we do not yet understand the function that life performs on Earth. That's the question I'm most looking forward to science answering.

Life is what makes the Earth unique to other planets, and we know for sure that biodiversity performs a function in the Earth's orbit, that is, it is important in the formation of the environmental conditions on Earth.

The first organisms on Earth consisted of only a single cell. And they had to live in the water, as the sun's UV rays made it impossible for living organisms to thrive on land. Some of the single-celled organisms developed photosynthesis - a process in which the sun's energy is converted into sugars and which secretes oxygen as a by-product.

Without these organisms, there would be no oxygen in the atmosphere or an ozone layer that today protects us terrestrial organisms from the sun's UV rays. The earth's environmental conditions have thus changed as various organisms have evolved.

At least as important as the climate crisis

At its core, the function that life performs on Earth is about combining the elements and molecules found in the earth in new and innovative ways. Whenever it has been possible to combine these raw materials in a way that releases enough energy to support life, an organism or group of organisms has evolved and managed to utilize that energy.

Science has brought us to the point where we can well describe how individual species transform elements and molecules in nature. To a large extent, we can also describe the function that individual species perform in the ecosystem of which they are a part. But we are not yet able to understand and describe in detail what function the total amount of life plays in the Earth's orbit.

To remain in the analogy of the poem, we do not yet understand the language that the species speak together.

However, it is extremely important that we get to know that language and that we do so soon. When we worry about man-made climate change, it is because we understand how our activities affect the amount of solar heat energy stored close to the Earth's surface, and that that impact has enormous consequences for the Earth's orbit. But in the end, it is not the Earth's energy balance alone that determines environmental conditions. It is the interaction between living organisms and the energy available that determines the environmental conditions on Earth.

At any point in the Earth's history, the prevailing environmental conditions will be a product of the interaction between the Earth's energy balance and the activity of the life that is present, and we know that the composition of organisms matters.

The fact that there is coal in the subsoil today, for example, is due to the fact that when green plants evolved, the bacteria that break down lignin - the substance that makes plants rigid - had not yet evolved. Therefore, large amounts of dead plant material accumulated, which were buried and later petrified, and thus formed the coal on which we are so dependent. Today, most of the dead plant material will be decomposed and thus not be converted to coal.

Climate change is an expression of changes in the Earth's energy balance. Since it is the interaction between the Earth's energy balance and biodiversity that determines the environmental conditions that prevail on Earth, it seems obvious that the 'biodiversity crisis' must be at least as important as the climate crisis.

In fact, the biodiversity crisis worries me in a way more than the climate crisis, because if the global community succeeds in managing its greenhouse gas emissions, the Earth's energy balance will, after thousands of years, return to 'normal' - that is, it will not be able to see signs of human influence. But when a species becomes extinct, it is gone forever. The earth will never be able to return to a state where human activities will not have left an imprint on biodiversity.

The boxes of science

The fact that we do not yet fully understand the crucial interactions between biodiversity and the climate is due to the fact that in science we have never really focused on interactions in the Earth's orbit. Since Newton's time, we have used a 'reductionist' approach to knowledge building. In science, we have focused on describing living and non-living objects in the university. We want to understand these objects down to the smallest detail, and we act as if we believe that a collection of our detailed knowledge within each discipline will miraculously lead us to an understanding of the Earth's orbit as a whole.

But we will never understand what a human being is, by simply gathering detailed knowledge from all medical specialties, for it is interactions between the various body parts and processes that make us who we are.

Gradually, we begin to understand in the health sciences how important the interplay between the various body parts and processes is for our circuits. Who, for example, ten years ago would have thought that our gut flora should be as important to our mental state and immune system as we recognize it to be today?

In science, we need to build a similar respect for the interactions that take place in the Earth's orbit. It is time that in our education and research we focus much more on the interplay that takes place between the objects classified under our different disciplines than on the objects themselves.

The study of the Earth's energy balance - that is, climate research - takes place within the disciplinary 'box' called geophysics, while our understanding of life on Earth is found in the biology box.

The two disciplines have developed vastly different approaches and languages, and they therefore find it very difficult to speak to each other. While climate scientists focus on the global energy balance, biologists usually look at individual species, processes or ecosystems. Geophysicists are able to quantify many of the processes related to energy balance based on well-established physical laws. It's not the biologists. Therefore, there is only a very primitive incorporation of the important biological processes in the climate models we rely on today when we try to imagine how the Earth's future environmental conditions will develop.

What we do not know about 'tipping points'

Understanding the significance of the interactions between biological and geological processes is absolutely crucial to developing reliable scenarios for how living conditions on Earth will be in the future. There is more and more talk about the risk and even the probability that global warming may cause the Earth to pass the so-called tipping points .

We know that there are processes and objects in the Earth's orbit that are either present or not present, all depending on the Earth's temperatures. When these processes or objects go from one state to another, we say that a tipping point is passed. We do not know at what temperature the various tipping points occur, but the risk of crossing tipping points in the near future fills more and more in the UN Climate Panel's reports.

The most worrying thing about tipping points, however, is that once they are passed, one cannot immediately make them return to the previous state. The ice in Greenland, for example, will - when the Earth reaches a certain temperature - not be salvageable, and cooling the Earth to the same temperature will not mean that the ice is restored.

Crossing many (but fortunately not all) tipping points will amplify global warming, and it is feared that some tipping points may lead others with them and thus initiate a kind of chain reaction in relation to Earth's warming.

Unfortunately, it is not only politicians who can determine the Earth's future energy balance (climate) at meetings such as those in Paris and Glasgow. There are also elements in the Earth's orbit that have a bearing on the establishment of environmental conditions.

We tend to focus on the tipping points that relate to knowledge in geophysics, for example the melting of the summer sea ice of Greenland and the Arctic as well as changes in the ocean current that bring us the heat from the Gulf Stream. However, there are also several known tipping points that belong to biology, such as the presence of the Amazon rainforest, high latitude forests, coral reefs, and the ability of ocean biological processes to absorb and store CO 2 from the atmosphere. The investigation of the latter is where my own research interests are focused.

The loss of coral reefs, which is also expected to occur even if the objectives of the Paris Agreement are met, will - as far as is known - not exacerbate climate change (but will, of course, have many other adverse consequences for humans). Crossing the other known biological tipping points will all have amplifying effects on global warming, but as we do not yet have a sufficient understanding of how they respond to temperature changes, their potential consequences for the Earth's future environmental conditions are not reliably built into the climate models used by the UN and others.

One could also mention here the melting of the permafrost, and how it will affect future environmental conditions, as another area that needs improvement in the global climate models. Melting of ice is a geophysical process, while the release of greenhouse gases caused by the melting is a biological process, so it can be difficult to determine whether an understanding of the future of permafrost belongs to the geophysical or biological science box.

The knowledge biologists have built up about species is both important and impressive. So we know a lot about the individual 'letters' that together make up the Earth's biodiversity alphabet, but we do not yet understand the 'language' that the letters together form. Knowledge of that language is a prerequisite for being able to predict the Earth's future environmental conditions, and what significance our mass extinction of biodiversity has for the Earth's orbit.

An economist once asked me in all seriousness what the 'optimal' amount of biodiversity is. How in the world would one be able to answer that question when one does not even understand the language that biodiversity speaks?

Katherine Richardson is a professor at the Center for Macroecology, Evolution and Climate at the University of Copenhagen and head of the Sustainability Science Center.