How do trees change the climate

Last Updated : July 18 2017

How do trees change the climate

by [email protected] Midwinter 2017 July 13

How do trees change the climate?

Environmental Issues For Real - Climate Change Policy


Climate change is inevitable. It has, and always will be, a feature of our planet. Why then are we so worried about it? We worry because, in our modern world of growing human numbers and affluence, rapid climate change affects us directly.

Changes in rainfall, temperature, frequency and intensity of severe weather, shifts in seasonality, and other locally significant effects, such as sea level rise and melting glaciers, are the visible consequences of climate change. These effects compromise food security, our water supplies, economic stability, and in extreme situations threaten lives.

Somewhere in our subconscious, we are also aware that climate change effects are acuter than they used to be.

A world containing 7 billion people who with the help of their immediate ancestors, have modified every corner, is not as buffered as it was.

Over time we have modified the environment to feed, clothe and shelter the generations. We have cut down trees, plowed fields, diverted rivers and reared livestock. The ability to make such modifications, and the responsiveness of the environment to the changes we have done, is why there are so many of us.

These changes to habitats have compromised environmental performance.

Recall that many a conservation scientist has warned of the dangers of biodiversity loss. They say that loss of diversity means fewer options for adaptation and delivery of ecosystem services. Where habitats are changed biodiversity is lost, and nature is not as robust and resilient as she used to be.

Consider a forest cleared for a wheat crop.

Wheat is an annual grass that dies back once the seed heads have matured, so part of the year there is only straw stubble in the field. Commonly farmers will plow in or even burn this stubble to leave the soil bare for many months. Exposed soil loses moisture, carbon and its biological activity. Dry, exposed soil is vulnerable to the wind and is readily eroded under torrential rains. Each year the grain crop feeds us only over time soil structure, moisture retention, and biological activity decline. Unless we apply fertilizer and insecticides yields fall too.

This bare soil and single species crop system that becomes dependent on inputs is not resilient to climate change. Warmer and drier or colder and wetter, extreme events and changed seasonality all affect productivity.

The original forest is well buffered against these effects. Trees are long-lived with deep root systems. Tree canopies and a layer of leaf mulch protects the soil surface to help retain moisture and maintain biological activity on the ground. Shifts in weather have little overall effect.

Unfortunately, it is not possible to make bread from trees.

While floods and drought deliver the sound bites and photo opportunities for climate change, intuitively we know that the modified landscapes that provide us with food and water are vulnerable to climate shifts. It is a worry. Not surprisingly we expect our leaders to implement policies some action to alleviate our concerns.

Humans are an action orientated species. We want to see something done.

The crux of the vexing debate over climate change policy is that something can be done about these changes to the environment. Alternatively, nothing can or needs to be done, depending on your point of view.

It also assumes that policy will not only generate that 'something' but that what is done will ultimately fix the problem.

It may be worth a moment away from rhetoric and spin to consider these assumptions once again.

The current policy debate is about greenhouse gas emissions. The premise is that human activities in the last 200 years in clearing land for agriculture and livestock, and in burning fossil fuels for energy and transport have triggered warming through an increase in the concentration of greenhouse gases in the atmosphere.

This we know, almost to the point of dogma. We also know that decreasing emissions is the chosen policy solution.

And so the political debate has become how to reduce emissions. What policies will slow energy consumption and the emission intensive activities without damaging economic activity? Is it a direct tax on emissions, a market trading scheme for emission credits, subsidies for alternative energy generation, regulation to limit emissions from vehicles, or combinations of a host of other options that are available.

The debate has rarely covered the consequences of climate change. It has focused on the action being taken that will fix the problem - efforts to stop climate change.

Future historians will applaud steps to shift from fossil fuel dependence. However, they will be confused by such a single focus. "Why," they will say, "was so little done to change land management when the consequences of climate change for food production and water supplies were so obvious."


Future historians will applaud steps to shift from fossil fuel dependence. However, they will be confused by such a single focus. "Why," they will say, "was so little done to change land management when the consequences of climate change for food production and water supplies were so obvious."

Hannah Midwinter
#1 Hannah MidwinterAuthor 18 March, 2014, 12:37 Hannah is a nature lover and passionate about helping people to go green. She loves gardening and recycling reusable materials.