Environmentally conscious consumers often ask me whether a real Christmas tree or an artificial one is the more sustainable choice. As a horticulture and forestry researcher, I know this question is also a concern for the Christmas tree industry, which is wary of losing market share to artificial trees.
And they have good reason: Of the 48.5 million Christmas trees Americans purchased in 2017, 45 percent were artificial, and that share is growing. Many factors can influence this choice, but the bottom line is that both real and artificial Christmas trees have negligible environmental impacts. Which option “wins” in terms of carbon footprint depends entirely on assumptions about how long consumers would keep an artificial tree versus how far they would drive each year to purchase a real tree.
Many consumers believe real Christmas trees are harvested from wild forest stands and that this process contributes to deforestation. In fact, the vast majority of Christmas trees are grown on farms for that express purpose.
To estimate the total impact of something like a Christmas tree, researchers use a method called life cycle assessment to develop a “cradle to grave” accounting of inputs and outputs required to produce, use and dispose of it. For natural Christmas trees, this covers everything from planting seedlings to harvesting the trees and disposing of them, including equipment use, fertilizer and pesticide applications, and water consumption for irrigation.
Life cycle assessments often will also estimate a system’s carbon footprint. Fuel use is the biggest source of greenhouse gas emissions in Christmas tree production. Using 1 gallon of gas or diesel to power a tractor or delivery truck releases 20 to 22 pounds (9 to 10 kilograms) of carbon dioxide into the atmosphere.
On the positive side, Christmas trees absorb and store carbon from the atmosphere as they grow, which helps to offset emissions from operations. Carbon represents about 50 percent of the dry weight of the wood in a tree at harvest. According to recent estimates, Christmas tree-sized conifers store roughly 20 pounds of carbon dioxide in their above-ground tissue and likely store similar amounts below ground in their roots.
However, using 1 gallon of gasoline produces about the same amount of carbon dioxide, so if a family drives 10 miles each way to get their real tree, they likely have already offset the carbon sequestered by the tree. Buying a tree closer to home or at a tree lot along your daily commute can reduce or eliminate this impact.
And natural trees have other impacts. In 2009, Scientific American specifically called out the Christmas tree industry for greenwashing, because growers’ press releases touted carbon uptake from Christmas tree plantations while ignoring pesticide use and carbon dioxide emissions from plantation management, harvesting and shipping.
Artificial trees have a different set of impacts. Although many people think shipping trees from factories in China takes a lot of energy, ocean shipping is actually very efficient. The largest energy use in artificial trees is in manufacturing.
Producing the polyvinyl chloride and metals that are used to make artificial trees generates greenhouse gas emissions and other pollutants. China is working to reduce pollution from its chemical industry, but this may drive up the prices of those materials and the goods made from them.
Moreover, to consider sustainability from a broader perspective, production of real Christmas trees supports local communities and economies in the United States, whereas purchasing artificial trees principally supports manufacturers in China.
Recently the American Christmas Tree Association, which represents artificial tree manufacturers, commissioned a life cycle assessment comparing real and artificial Christmas trees. The analysis considered environmental aspects of sustainability but did not examine social or economic impacts.
The report concluded that the environmental ‘break-even’ point between a real Christmas tree and an artificial tree was 4.7 years. In other words, consumers would need to keep artificial trees for five years to offset the environmental impact of purchasing a real tree each year.
One major shortcoming of this analysis was that it ignored the contribution of tree roots – which farmers typically leave in the ground after harvest – to soil carbon storage. This omission could have a significant impact on the break-even analysis, given that increasing soil organic matter by just one percent can sequester 11,600 pounds of carbon per acre.
Consumers can’t affect how farmers grow their live trees or how manufacturers produce artificial versions, but they can control what happens after Christmas to the trees they purchase. For artificial trees, that means reusing them as many times as possible. For natural trees, it means recycling them.
This is essential to optimize the carbon footprint of a real tree. Grinding used Christmas trees and using them for mulch returns organic matter to the soil, and can contribute to building soil carbon. Many public works departments across the United States routinely collect and chip used Christmas trees after the holidays. If local tree recycling is not available, trees can be chipped and added to compost piles. They also can be placed in backyards or ponds to provide bird or fish habitat.
In contrast, if a used tree is tossed into a bonfire, all of its carbon content is immediately returned to the air as carbon dioxide. This also applies to culled trees on tree farms. And if used trees are placed in landfills, their carbon content will ultimately return to atmosphere as methane because of the way materials buried in landfills break down. Methane is a greenhouse gas 21 times more potent than carbon dioxide over a century, so this is the most environmentally harmful way to dispose of a used tree.
All kinds of factors influence choices about Christmas trees, from fresh trees’ scent to family traditions, travel plans and the desire to support farmers or buy locally. Regardless of your choice, the key to relieving environmental angst is planning to reuse or recycle your tree. Then you can focus on gifts to put under it.
Trees are not just for Christmas. They are crucial in keeping our living planet alive so we need to do our best to protect them. If you want to do more than recycling Christmas trees you can donate to Cool Earth below, a non-profit organisation working with local communities to protect rainforests.👇
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Join us for the second of our Kinder Conversations - the Sky has a Limit.
Following our investigation into the Future of Meat in February, we've turned our attention to the sky. We'll be talking about whether air travel can be more sustainable, and how.
We're delighted to be hosting this event in collaboration with our friends at TQ, the Amsterdam tech hub where we're based.
📅 When Monday 17 June 18:30 - 20:30
📭 Where TQ, Singel 542, Amsterdam
🎯 Why should I fly Kinder? To hear about the latest research and technology making air travel more sustainable. To find out what you can do to reduce the impact your flights are having. To share a drink with like-minded travelers, and sample some of our vegan snacks (including beloved Professor Grunschnabel ice cream, as seen at the Future of Meat event)
Here at Kinder, we believe that greener travel is one of the key ways in which we can tackle the climate crisis. Travelling green can mean a lot of things, but right now we’re concerned about the aviation industry.
If aviation were a country, it’d be a top 10 polluter - and C02 emissions from air travel are growing many times faster than any other form. We’re already in a very dangerous position, and although there are many potential solutions, we sometimes feel overwhelmed and uncertain about what to do about it.
That’s where Kinder Conversations comes in.
Kinder Conversations is a series of events which delve into the biggest issues facing the world.
At the Sky has a Limit, we’ll be bringing together representatives from research and technology, the aviation industry and the not-for-profit sector to talk about sustainable air travel. We’ll hear more about the problem, and a lot more about the solutions.
Plus, there’ll be time to get a drink from TQ’s bar (buying a drink helps our friends from TQ support more events like this), try some vegan ice cream, and chat to fellow travellers about the steps you can take to travel greener.
✈️ Are you ready to #flykinder? Then secure your boarding pass here.
I don't have a driving license and when pressed about getting one by friends tired of chauffeuring me around I usually say I will only get one if I can drive something cool, like the Batmobile or a flying car. Unfortunately, I might have to honour that promise as it seems that flying cars are finally taking off (alas, no commercial Batmobiles in sight).
Indeed, several promising startups around the world are working to deliver the "car of the future" over the next few years. Like the Dutch company PAL-V that showed off a limited edition of its flying car at the Geneva Auto Show in Switzerland.
The PAL-V is a hybrid between a car and a helicopter (or more precisely, a gyrocopter), able to reach a top speed of 160 km/h on the tarmac but also get airborne in just 5 minutes, hitting airspeeds of 180 km/h over a range of up to 500 km. But since buying a PAL-V will set you back around € 350,000 I might have to pass on this one. Moreover, flying this beauty requires not just a driving license but also (understandably) a license to fly, and that's just too much for me.
Thankfully, other companies are developing vehicles that need no driver at all. Aerospace manufacturer Bell Helicopter, for example, is working on Nexus, an air taxi capable of taking off and landing in the middle of a city (whereas the PAL-V still needs a runway, albeit short, to get airborne).
Called VTOLs (short for Vertical Take Off and Landing), these aircraft aim to become sort of an Uber of urban air travel, bringing customers to the opposite part of the city or even to a nearby city in a matter of few minutes.
If you're at JFK airport in New York, for example, and have a meeting in Manhattan, instead of embarking on a 1-hour, Cosmopolis-style taxi ride, you could just hail a flying car and be downtown in 5 minutes.
Futuristic as it may sound, concrete plans to make it come true are underway. Earlier this month, German startup Lilium successfully completed the first test of its new five-seater Lilium Jet, an electric vehicle that, according to the company, will have a range of 300 km and a top speed of 300 km/h.
The reason electric flight is such an exciting area of research is not just because flying taxis will allow a handful of high rollers to drastically cut on their commuting time. Electric flying cars might be really good for the environment too.
A recent study published by Nature highlighted that, in some cases, flying cars could eventually be greener than even electric road cars, cutting emissions while reducing traffic on increasingly busy roads.
Moreover, developments in the field of flying cars could also boost the research on electric flight at large, including long haul electric flights, sort of the Holy Grail of aviation. And, as known, the civil aviation industry needs to find effective ways to lower its carbon emissions as soon as possible.
However, as explained by Hugh Hunt in an article on The Conversation that we republished here on Kinder World, "gaps in necessary technology and practical uncertainties beyond the cars’ promising physics mean that they may not arrive in time to be a large-scale solution to the energy crisis and congestion."
Let's get this one thing straight: most people prefer flying to other modes of transport, and we seem to do it more and more often. The airline industry is booming and 4.1 billion passengers have been transported last year. Almost every figure one looks at shows the impressive increase in flights over the last two decades.
Alexandre de Juniac, head of the International Association for Flight Transport proclaims: “In 2000, the average citizen flew just once every 43 months. In 2017, the figure was once every 22 months. Flying has never been more accessible. And this is liberating people to explore more of our planet for work, leisure, and education. Aviation is the business of freedom."
However, this ‘business of freedom’ runs on fossil energy carriers as planes still almost exclusively fly on kerosene. Kerosene is a fuel produced by oil refining and carbon dioxide (CO2) is the major product of burning kerosene. The 2-5% of all global CO2 emissions the aviation industry emits is caused by its fuel consumption (and choice). And unlike other fuels like diesel or gasoline, airlines don't pay taxes on kerosene in most countries — making cheap air travel possible.
In 2018 Europe’s biggest airline Ryanair became number 9 in the list of Europe’s biggest CO2 emitters and still claims to be the ‘greenest and cleanest airline’. Andrew Murphy – the aviation manager at the European Federation for Transport and Environment — argues that Ryanair the new coal when it comes to climate pollution. Ryanair CEO Michael O’Leary, on the other hand, dismisses such claims by saying the claims are ‘’complete and utter rubbish’’.
Other airlines, like KLM who partly uses renewable jet-fuel, are acknowledging the problem but they aren't too far behind Ryanair on the list of emitters.
The growth of the industry is not expected to slow down. India and China are the biggest growth markets, the latter alone is building 200 new commercial airports in the next ten years. Moreover, industry forecasts suggest that emissions will rise by 700% until 2050 which amounts to more than 4% of the world’s remaining carbon budget.
If we want to reach the goals of the Paris Agreement, every the average earthling has a quota of two tons of CO2 per annum but just a return trip between New York and Amsterdam generates three tons already.
Compared to other modes of transport planes are the biggest CO2 emitters per travelled kilometre followed by cars, buses and finally trains which are the least polluting. The CO2 emissions, however, are only one half of the medal. The impact of flying on global warming is different than most other transport as it happens in the air high above the ground where the processes that cause or reduce global warming happen. These include CO2 and nitrogen oxide emission but also cloud formation, ozone and soot as well as methane reduction.
The climate impact of the emitted greenhouse gases in the stratosphere are three times higher than on the ground. Flying also causes condensation trails and fog clouds in certain weather conditions. Such clouds can have a warming or a cooling effect on the climate. One way to improve the climate effect of flying would be planning better routes where warming clouds are avoided and the formation of cooling clouds is favoured — our current routes have an overall warming effect.
So, hypothetically, some flights with clever flight-route planning might even reduce global warming. However, as we don't have time to hypothesise, we need to find and urgently implement other ways to bring down the impact of flying, like using better fuels or even better planes.
This article was written by Eric Schuler for Kinder World. Schuler is a PhD candidate at the University of Amsterdam and works on new industrial sustainable chemistries to turn captured CO2 into useful things such as plastics or fuel. He's also a photojournalist with an interest in climate and land-use change.