Lawn of the Dead: How Cutting your Grass Affects Wildlife

Why do we cut our grass? The short answer is that we think it makes our gardens look neat and respectable. What would the neighbours think if our grass was long and full of weeds? What this kind of thinking fails to consider is the massive toll that lawn mowers have on local wildlife. All ecosystems are fragile and vulnerable to devastating chain reactions. By reducing the diversity of the plants on your lawn, you greatly reduce the hospitability of that environment for insects like bees, beetles and butterflies. This, in turn, has an effect on the food supply available to birds and small mammals. Some animals like mice and hedgehogs are often killed directly by the blades of mowers. On top of all this, most of us cut the grass with either petrol-powered or electric mowers, both of which hasten and intensify climate change, the greatest threat currently facing people and animals alike.

Humans have an obsession with shaping and controlling the world around us. Vast tracts of land are occupied either by our urban environments, crops or livestock. In the suburbs of our cities lie hundreds of millions of houses, with hundreds of millions of gardens. The reason gardens are so ubiquitous is that we psychologically require some part of our artificial environment to at least resemble nature. That is also why the paintings we hang on our walls often depict natural landscapes. While grass that is cut every week or two resembles nature, it is by no means natural. The hormones which suppress horizontal growth are in the tips of each blade of grass, which means that frequent cutting eventually creates a dense carpet which is impenetrable to anything but the grass.

To a bee, the difference between a well-cut lawn and a natural meadow is like the difference between a desert and a buffet. Global insect populations have been crippled in recent years by a combination of pesticides, herbicides, habitat loss and overactive lawnmowers. A 2017 study found that the number of flying insects in Germany has dropped by more than 75% in less than 30 years. Though you may think they’re creepy and unnecessary, insects serve a vital role in almost all ecosystems. Just like any other chain, if you break one link in a food chain, the whole thing becomes useless. The issue is not just the food supply of other animals, but also that some insects serve a critical function as pollinators. Three quarters of the world’s flowering plants and a third of all food crops depend on pollinators for their survival.  

Plants really are the bedrock of all ecosystems. Animals have no way of converting the energy of the sun into energy that we can use to do things like move and breathe, so we rely on photosynthesising plants for all of our nutrients. Even if you eat a lot of meat, poultry and fish, it’s important to remember that those animals only survived their first day on earth because of the nutrition they got from plants. Whether it is corn-fed chicken or grass-fed beef, we owe everything we eat to plants. Without pollinators like bees, many plants are left with no way to reproduce and, thus, no way to survive.

Petrol-powered lawnmowers are not regulated in the same way that petrol-powered vehicles are. The U.S Environmental Protection Agency (EPA) estimates that each petrol-powered lawnmower produces as much air pollution per year as 43 new automobiles being driven 12,000 miles each. If you’re thinking that this section doesn’t apply to you since you have an electric mower, it is important to remember that the electricity required to power your mower comes from a power plant that most likely used fossil fuels to generate the electricity.

If it is a choice between the two, however, electric mowers are the much greener choice. The emissions are more controlled and you do not need to use fossil fuels to transport the petrol all the way from a refinery to your back garden. In addition to this, the EPA estimate that 17 million gallons of petrol are spilled on lawns each year by Americans refuelling their lawnmowers. That is 6 million gallons more than was spilled in the infamous Exxon Valdez oil spill in 1989. Manual mowers which are powered by the elbow-grease of the user are both cheaper and better for the environment than either of the other kinds. If you are not able to push a manual mower for that long, solar-powered models are also available.

Lawn mowers are expensive. The fuel or electricity which powers them is expensive. On top of that, the actual process of cutting the grass requires time and effort and is widely considered to be a chore. A 2008 poll found that 58% of Americans surveyed said that they disliked cutting their grass. Ian Graber-Stiehl, in an article for Earther, claims that Americans spend between 47.8 and 82 billion dollars per year on lawncare and landscaping, compared to the 49.4 billion dollars they spend on foreign aid. Like smokers or alcoholics, we are paying through the nose to shoot ourselves in the foot. And for what? So that the neighbours don’t look down on us? My personal view is that if having long grass causes someone to lose respect for you, then that person’s respect is something you can do without.

For me, the important question to consider here is whether the benefits of cutting the grass outweigh the costs. I would argue that the answer to this question is a definitive no. The list of cons includes the killing of wildlife, contribution to climate change, high costs, noise pollution, air pollution and the fact that most of us hate doing it. The only real pro is that cut grass looks better, but even that is a matter of taste.

Personally, I think that a natural garden, with all its colour and movement, looks far more appealing than a still and monotonous carpet of green. It is important to point out that this is not an all-or-nothing situation. If you don’t want to abandon your mower altogether, you can still allow a neat patch of grass to grow long or mow a path to a small clearing where you can immerse yourself in the wild beauty that will surround you.

We need to change the perspective on this. We should not look down on people with long grass, quite the opposite! Those people are the ones who are helping their local environment by providing food and shelter for wildlife and cutting down on their carbon emissions in the process. In the age of anthropogenic climate change and mass extinction, the aesthetic appeal of our gardens needs to be lower on our list of priorities than helping animals to thrive.

We have brought the natural world to its knees in so many ways. The continued existence of every species on earth needs to be our top priority, not because they cannot take care of themselves, but because we are the ones who have endangered them. We have a responsibility to fix what we have broken and not only does leaving your grass to grow achieve that goal, it also saves you money and reduces greenhouse gas emissions. It is not often that you find a free way to help the environment, let alone one which will save you both money and effort. This is one of the rare win-win ways in which we can help our fellow inhabitants of earth get back on track.

Win Win Win Win: The Magic Science of Plasma Waste Converters

First Published in the UCD College Tribune

Humans have an incredibly extensive waste problem. Right now, most of that waste is sent to landfills where it takes up space for thousands of years, leaching harmful chemicals and gases into the soil and atmosphere. Alternatively, we send our waste to incinerators which burn it for energy, but which release harmful greenhouse gases (GHGs) and toxic by-products in the process. A large proportion of our plastic waste ends up in the ocean, where it strangles and poisons fish, seabirds and marine mammals. What if I told you that there was a way to get rid of almost any type of waste in one machine, that the machine would release no harmful chemicals or GHGs, and that the process would produce useful by-products and excess energy that could be sold back to the grid? Such a machine exists right now; the plasma waste converter (PWC).

While incinerators are able to extract about 15% of the potential energy from rubbish, PWCs can extract an incredible 80% through a process called ‘gasification’. Plasma is ionised gas, meaning that it contains roughly equal numbers of positively charged ions and negatively charged electrons. It is often called the fourth state of matter since its characteristics are so different to those of liquids, solids and gases.

One way you can make plasma is by creating an arc of electricity between two rods, then passing a gas like argon through it. This set-up is known as a plasma torch and can heat gases to a higher temperature than the surface of the sun. Plasma torches were invented by NASA in the 60s to test how much heat the hulls of their spaceships could withstand. The crucial difference between using a plasma torch and using an incinerator is that in PWCs, combustion doesn’t take place. That means no smoke, no GHGs and no ash. The plasma breaks down the bonds between atoms, separating them into very simple forms. Despite the extremely high temperatures, it would be wrong to say that the waste is being ‘burned’; rather it is being decomposed at an accelerated rate.

One of the products of gasification is, you guessed it, gas. This energy-rich gas, known as syngas, is largely made up of hydrogen and carbon monoxide. Syngas mainly comes from the gasification of organic matter. As the gas expands, it spins a turbine, generating electricity. The high temperature of the gas can also be used to evaporate water, generating steam to turn another turbine. The syngas itself can then be burned for fuel or scrubbed with water and released safely. Remember, all of this energy production and revenue is coming from rubbish. We are talking about the plastics that are decimating marine life. Metals, fabrics, wood, even toxic or hazardous waste from industrial run-off or medical facilities. This is stuff that we desperately need to get rid of and by getting rid of it like this, we can also take some of the stress off an already strained energy production sector.

The solid by-product of gasification is called ‘slag’. Slag is produced mainly from inorganic materials like metals. It can be used in construction to bulk up concrete and tarmac, making it a very useful commodity. The molten slag also pools at the bottom of the chamber and helps to maintain the temperature, reducing the energy consumption of the PWC. The real magic happens when you pass compressed air through molten slag to create a material known as ‘rock wool’. Rock wool is currently made by drilling into rock, melting it down and spinning it in a centrifuge. Made in this way, rock wool is sold at one US dollar per pound. When it’s made of rubbish instead, it can be sold at just ten cent per pound.

Rock wool can be used in a number of ways. As an insulation material, it is twice as efficient as fibreglass and could significantly decrease heating and air conditioning bills, further reducing the carbon footprint of gasification. Surprisingly, you can also hydroponically grow plants from seed in rock wool. Perhaps its most amazing use is that it can clean up oil spills. Rock wool is lighter than water and extremely absorbent. This means that if you spread it out over the surface of an oil spill, it will float and absorb all the oil. The rock wool can then be collected with relative ease. Slag and rock wool are two more saleable products that can increase the economic viability of plasma waste conversion.

PWCs are currently being built all around the world. Some plants are already so efficient that they need to take rubbish out of landfills to use as feedstock. There is even a mobile plasma torch on the back of a truck in the US which can be jammed straight into landfills, which act as makeshift gasification chambers. The need to reduce GHG emissions and simultaneously fix our massive waste problem has generated huge interest in PWCs in recent years. Landfills have only one way to make money; they charge you a ‘tipping fee’ for getting rid of your waste. Since PWCs can generate revenue from both energy production and by-products, they can make their tipping fees much more competitive.

So why haven’t these things solved the problems of pollution and climate change already? The answer is largely that PWCs are still a relatively new technology. The cost of building and operating one is still much higher than that of some of its competitors including landfills and incinerators. There has not yet been standardisation of the design and thus the huge and complex machinery must be custom-built every time. The energy needed to power PWCs is also very high, especially compared to incineration, which requires only a match. It must be said, however, that although it takes a lot of energy to run a PWC, you will very quickly make all that energy back and more. PWCs are extremely efficient long-term; unfortunately, short-term profits dictate much of what happens in society.

One worry is that by making waste a profitable commodity, we encourage people and companies to keep polluting with impunity. The best way to solve pollution is not to pollute more and then clean it up better. It is to reduce the amount of pollution we are producing, whether that is by reducing our individual consumption, or by researching innovative ways to package our goods without making a mess. There is, on the other hand, already a lot of waste out there, languishing in landfills and contributing to the decimation of marine ecosystems. The best thing to do with all that waste is to get rid of it with the fewest possible emissions and the most possible benefits. PWCs may be just the technology for the job.

The price of fossil fuels is slowly being raised by various economic policies to reflect the cost to life on earth and we need to find as many alternative sources of energy as we can. With countless landfills already full and the world still producing around 2 billion tonnes of waste per year, rubbish will not be scarce for a very long time. This really is a win win win win win. One machine can get rid of harmful waste, cut GHG emissions, produce fuel, energy and construction materials and clean up oil spills all while making a profit. An investment in plasma waste converters is not only economically sound, it is also an investment in the future of our planet.