How Plants Help with Climate Change

Have you ever wondered what role your garden might play in the grand scheme of climate change?

Climate change is primarily driven by the increase in greenhouse gases in our atmosphere. These gases trap heat from the sun, causing global temperatures to rise—a phenomenon known as global warming. The effects are far-reaching, from melting polar ice caps and rising sea levels to more frequent and severe weather events.

According to NASA, the global average surface temperature has risen about 1.18 degrees Celsius since the late 19th century.

But here’s where it gets interesting: plants, including those in your backyard, can be one of our most effective tools in battling climate change. A mature tree can absorb up to 22 kg of CO2 per year.

The problem is, most of the conversations around this topic are overly simplified and rely on disempowering solutions rather than empowering ones (such as giving up on travelling).

Role of Plants in Mitigating Climate Change

Plants play a significant part in mitigating climate change, primarily through a process known as carbon sequestration. This involves capturing and storing atmospheric carbon dioxide—one of the primary greenhouse gases.

But that’s not all; plants also provide various other environmental benefits, such as reducing soil erosion, improving water quality, and providing habitat for wildlife. Our focus should be on successfully establishing trees rather than merely planting them.

Mature trees sequester more carbon than their younger counterparts, so ensuring their survival and growth is key to maximising their carbon-capturing potential. If we’re going to take climate change seriously, we need to innovate a new way of producing sustainable energy. But until then, cultivating healthy plants is one of our best tools to mitigate our emissions

Understanding the Terrestrial Carbon Cycle

The Basics of The Carbon Cycle

To grasp how plants help fight climate change, we’ll first need to understand the carbon cycle. This process begins with photosynthesis, where plants absorb carbon dioxide from the air and sunlight to produce glucose, which fuels their growth.

Essentially, what plants are doing is taking the “carbon” out of the carbon dioxide, and then releasing the “dioxide” part as oxygen molecules along with water out of their stomata in a process called “transpiration.”

During this process, some carbon is released back into the atmosphere. However, a significant portion remains stored within the plant and soil, contributing to the terrestrial carbon cycle. Animals and fungi eat this carbon, and release it back into the soil in our excretions and into the air as our out-breaths which include carbon dioxide.

This is an oversimplification of the carbon cycle, of course. We haven’t even touched on the ocean’s role which is a significant omission.

Stable vs Labile Carbon

Within this cycle, carbon exists in spectrum between two stable and labile forms.

Stable carbon is stored long-term, often in the form of fossil fuels like coal and oil beneath the earth’s surface for millions of years. Biochar, which is a buzz term for biological material that’s been burned at a low temperature with low oxygen until it’s become charcoal, is another extremely stable form of carbon.

In contrast, labile carbon is readily available and frequently exchanged between plants, animals, and the atmosphere. This includes leaves that rot on the soil’s surface, being eaten by organisms, which then die and are eaten by other organisms, with a little bit being slowly released as the out-breath of these organisms at every step.

It can be tempting to rush to the conclusion that “labile forms of carbon are bad, and stable forms are good.” But it’s important to understand that labile sources of carbon are vital for life on Earth, contributing to the functioning of ecosystems and the biodiversity within them.

The problem is that too much stable carbon in the form of fossil fuels has been released into labile forms – we can’t blame animal burps or farts which are part of the natural cycle.

Sustainable Urban Drainage Systems (SUDS)

Rainfall Gardens and Bio Swales

Rainfall gardens and bio swales are two components of Sustainable Urban Drainage Systems (SUDS). A rainfall garden is a planted depression that allows rainwater runoff from surrounding areas to be absorbed.

Bioswales are similar to rain gardens in terms of biodiversity support and capturing water, but the difference is that bioswales allow some of that rainwater escape into stormwater drains. However, they do filter that water before it escapes using the power of plants.

These systems can significantly reduce flood risks by slowing down and storing runoff, instead of overwhelming our urban infrastructure.

In addition to this, some SUDS can recharge underground aquifers. This process provides a source of water during periods of drought, reducing the need for unsustainable irrigation methods.

It’s important to remember that rainwater is a resource, not a waste product. Capturing and reusing it reduces our reliance on mains water for irrigation, it helps improve soil quality, and increases transpiration which cools urban environments down and can increase rainfall.

Role of Biodiversity in Climate Change

Importance of Plant Biodiversity

A diverse range of plant species can sequester more carbon than a monoculture because different species excel in different conditions. Thus, a biodiverse ecosystem is more effective in capturing and storing carbon over a range of environmental conditions as the weather differs year to year.

On top of this, by providing food, shelter, and nesting sites for various species, we can encourage a healthy ecosystem, with each species playing a unique role in maintaining the balance so that we aren’t simply left with pests and weeds.

It’s also worth noting that plants provide habitats for beneficial bacteria and fungi. These organisms contribute to critical processes like decomposition and nutrient cycling, further enhancing the ecosystem’s resilience against climate change.

How to Encourage Biodiversity in Gardens

by selecting a variety of plants that thrive in your local conditions. Include a mix of trees, shrubs, and flowering plants to provide different habitat structures.

It might be tempting to plant locally indigenous plants, and I wouldn’t discourage you from doing that. However, you might find that the environments they’ve adapted to are very different to the urban environment you’re trying to plant them into.

Sometimes, you’re better off choosing native cultivars that have been bred with superior characteristics for the urban environment. They’re often more abundant with their flowers, hardier against environmental conditions, and will be much healthier than plants that are less resilient.

Provide habitat and food sources by incorporating plants with pollen, nectar, fruits, and seeds. And plant lots of them so that birds, insects, mammals, reptiles, amphibians and other critters have lots of places to hide and eat.