Climate change: the big picture is being missed

Imagine that we have persisted in driving at speed along a track that, for miles, has been shaking a beautiful car to pieces and littering the ground with wreckage. But our eyes are fixed on the temperature gauge and all we know to worry about is overheating. Only when the engine is becoming too hot do we realise that the cooling system of our vehicle is connected to lots of other parts, including some of those that have fallen off.

The metaphor may not be perfect but it draws attention to the fact that climate is an integral part of the way the world works. It is not a separate issue.

Everything is interconnected. The world is a hierarchy of systems. Nobody knows how many species there are among the living components, much less the exact roles they have in the ecosystems that we know about. But they do play a part; they don't just exist in numbers within categories like 'endangered,' 'threatened,' or 'pest'. And the systems work on vastly different levels. At the smallest level, individuals are evidently walking ecosystems of even greater complexity than we might have guessed.

As parents have always known, the behaviour of babies is largely determined by signalling that goes on between the brain and the belly. What science has recently discovered is that the brain receives some signals from communities of microbes in the gut. In laboratory animals, at least, the microbes' chemical messages can influence mood, mental health and social behaviour. It is now reasonable to wonder whether microscopic forms of life in a person's gut could be involved in conditions such as depression and autistic spectrum disorder.

Research findings like this make good topics for wider publication because the recipe for getting articles published and widely read starts with finding interesting topics, then giving them catchy titles and keeping the writing focused. It's no good rambling on, trying to join all the dots that might come into view as you explore your subject and get into your stride.

So it follows that day-to-day reporting on anything involving the natural world is likely to be something of a snapshot, some tiny aspect of the bigger picture without the interconnections. In these times of information overload, readers are doing well to come away with a proper grasp of whatever works best in the limited space beneath a catchy title.

Broadening the picture

The study of earth's climate is as big as it gets in terms of system science so making sense of climate change is mainly the work of specialists who feed enormous amounts of data into computer models. The specialists' consensus, which is causing such a fuss in domestic politics, is that gases, largely released from burning fossil fuels, are amounting to more than the earth can cope with in its present state so the gases are accumulating in the atmosphere. Because of the greenhouse effect the lower part of the atmosphere is warming up and the climate is changing in ways that have no precedent during the past few thousand years - if ever.

As temperatures increase, polar ice melts, sea levels rise, oceans become more acidic, and extreme weather events become more frequent. There will be many regional and less predictable consequences and the cumulative impact on economies around the world is likely to vary enormously between nations. Changes to the temperature and chemistry of the oceans will have a severe impact on corals and on the many marine species that depend on the reefs. On land, it is hard to see how the net impact on biodiversity can be other than negative when the climate is changing swiftly away from that to which species have long been adapted.

But the fact remains that the major destroyers of wild nature are the same as they have been for a long time. Most destruction is still a direct consequence of human activities - including some of those most responsible for the release of greenhouse gases. We can expect a changing climate to make matters worse overall but on present trends the onslaught against wild nature is set to continue, with or without climate change.

People and the planet

Fisheries reveal the pressure. In 1950 the global fish catch was 28 million tonnes and it seemed inconceivable that the oceans, covering 70% of the earth's surface, would be overfished within a person's lifetime. The catch peaked at 130 million tonnes in 1996, since when it has been declining despite increasing effort by the world's industrial fleets. In 1950 the human population was close to 2.5 billion. It is now 7.8 billion and set to reach 8 billion in the next three years. The last billion was added in a twelve-year period. A billion is a number that slips easily off the tongue so it is worth bearing in mind that a clock takes more than 30 years to count it in seconds.

Life inside the greenhouse

The messages commonly being hammered out in the everyday news are as simplistic as political slogans. We are told that CO₂ emissions must be reduced, and quickly, because time is running out to save our precious world. Climate activists carry the messages on placards. The implication, intended or otherwise, is that all would be well with the planet if we could stop burning fossil fuels. So simple. If only it were true!

The earth's operating systems are being affected by a combination of human demands for energy, land, water and other resources. Soil, for instance, is a bigger carbon sink than all the trees and other vegetation that grow upon it, so land degradation contributes substantially to climate change. About a quarter of the world's land area is now degraded, let alone deforested. Wetlands are being lost particularly rapidly yet they are especially important in the carbon cycle, as well as providing many other ecosystem services.