How green is your Christmas tree?

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Ian D. Rotherham, Sheffield Hallam University

There’s no way around the fact that Christmas has a large carbon footprint, from the travelling we do to the presents we give and the large amounts of food we eat. But it is possible to at least reduce the negative impacts. With climate change and carbon dioxide levels now major sources of concern, surely it is time to see what can be done to be friendlier to the environment, and the Christmas tree is a good place to start.

As editor of an academic journal on arboriculture – the cultivation of trees – this is something I know a bit about. There are various aspects to assess: how the trees are grown, how many years they are used for, and how they are disposed of or recycled. For artificial trees, we also need to consider what they are made of and how and where they are manufactured.

For real trees, there is a question of where they comes from and how they were grown. Sourcing your tree locally will cut down on transportation costs and emissions and support local jobs too. Habitat may be another issue, since trees grown on moors, heaths, and peat bogs are hugely damaging with massive losses of peat-carbon and biodiversity, and increased downstream flooding. It’s better to instead choose trees grown on arable fields or “improved” grassland of little ecological interest.

Don’t worry about the emissions

When buying a Christmas tree, people may worry about carbon dioxide released back into the atmosphere when it is cut down and then, once used, disposed of. But there are issues and complications with this. Yes, you are cutting down a young tree which will either be thinned from a plantation of larger trees or be part of a single-aged crop all cut down at the same time. In the first instance, the loss of your tree will make no difference whatsoever to the carbon balance of the plantation since the other trees nearby will grow in compensation because competition for light and nutrients is reduced.

Even when a tree has been harvested as part of a single-aged crop, a proportion of its organic matter (and carbon) will remain as the dead root material and fallen leaves to be reincorporated into the soil’s carbon-bank. And if you recycle the tree after use as woodchip, then all that material is returned to the soil as well, and only a small proportion will return immediately to the atmosphere.

If you burn the old tree, then clearly both carbon dioxide and other pollutants go immediately into the air. However, even in this scenario, your tree can only return to the atmosphere the carbon which it took out in the first place – so there is zero net carbon loss. Our real concerns for carbon release are from burning of fossil fuels from below ground, and from damage to long-term carbon storage in peat bogs and fens. Disposal at landfill is much more damaging than incineration.

There is not much to choose between the different species of Christmas tree, at least in terms of carbon impact. There are issues, though, in terms of how trees are grown and particularly the use of pesticides in their cultivation, and potential damage to precious wildlife habitats. A recent example is the damage wrought to a peat bog in Cumbria by inappropriate planting of conifer trees.

An artificial tree, on the other hand, can have a relatively significant carbon footprint depending on what it is made from, and most of all, how many years it remains in service. Spread over ten years, the impact is negligible, but if it has been manufactured abroad, then the immediate carbon footprint is considerable.

How to reduce your tree’s footprint:

1) Buy a real tree, put it in a pot and use it over several years and finally plant it outside to live on. That way you will even mop up a little of your carbon footprint from other Christmas celebrations.

2) Recycle your real tree after use as woodchip or compost. Don’t bin or burn it.

3) Buy local and from a charity.

4) Avoid trees brought in from a distance and especially from an environmentally damaging source – ask the retailer where they are from. Better still, go direct to a local farm shop or National Trust site that is both producing and selling trees.

5) Ask for organically grown trees if possible.

6) Some growers make a donation per tree to an environmental charity – so ask when you buy.

Any “consumption” of goods has environmental impacts, but that is an unavoidable part of life. Christmas trees provide lots of pleasure for many people – just try to boost the good aspects and avoid or minimise the bad ones.

Ian D. Rotherham, Professor of Environmental Geography and Reader in Tourism and Environmental Change, Sheffield Hallam University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Why microplastics found in Nigeria’s freshwaters raise a red flag

Plastic pollution remains a topmost environmental concern
Pius Utomi Ekpei/AFP via Getty Images

Emmanuel O. Akindele, Obafemi Awolowo University

Freshwater ecosystems are a priority for environmental scientists because they affect the health of animals and plants on land too – as well as people. They provide food, water, transport and flood control. Freshwater ecosystems also keep nutrients moving among organisms and support diverse forms of life.

Freshwater systems make a big difference to the quality of life in any human society. But they are under great pressure. Freshwater biodiversity is declining faster than terrestrial biodiversity.

Among the three major types of habitats – terrestrial, freshwater and marine – freshwater accounts for less than 1% of the earth’s surface. Yet these habitats support more species per unit area and account for about 6% of the world’s biodiversity.

One of the biggest stresses on freshwater ecosystems is the presence of plastics. Some microplastics – tiny pieces of plastic that have broken down from bigger pieces – get into water from various sources. Some are introduced from industrial sources like cosmetics, toothpaste and shaving cream. Another major source is dumping of plastic waste like bags and bottles.

In Nigeria, an important source is the plastic sachets that contain drinking water. Over 60 million of these are consumed in a day.

Ultimately all these types of plastic waste find their way to the aquatic environment. There they stay in the water column, settle on river beds or are ingested by aquatic animals.

My research group set out to assess the load and chemical nature of microplastics in two important rivers and Gulf of Guinea tributaries in Nigeria. We looked for the presence of microplastics in aquatic insects since they often dominate aquatic animal life. Most also spend their adult stage in the terrestrial environment, once they emerge from their larvae. We found that microplastics were present in large quantities in the insect larvae. The insects are part of a food chain and could transfer the harmful effects of microplastics throughout the chain.

This further reinforces the urgent need for Nigeria to go ahead with measures to reduce the use of plastic bags and single-use plastics.

The research findings

We used three of the rivers’ aquatic insect species as bio-indicators and found that all three had ingested microplastics from the two rivers. The ingested microplastics include styrene-ethylene-butylene-styrene, acrylonitrile butadiene styrene, chlorinated polyethylene, polypropylene, and polyester. The quantity of microplastics ingested by the insects was fairly high, especially in the Chironomus sp. which is a riverbed dweller recorded in the Ogun River.

The diversity of plastic polymers recorded in these insects suggests a wide range of applications of plastics in Nigeria.

The three insect species spend their larval stages in the water and later migrate to land in the adult phase. The concern is that the insect larvae could serve as a link for microplastics’ transfer to higher trophic levels in the aquatic environment. Also, the adults serve in the same capacity in the terrestrial environment. A trophic level is the group of organisms within an ecosystem which occupy the same level in a food chain.

Dragonfly larvae in the water are eaten by fish, salamanders, turtles, birds and beetles. Adult dragonflies on land are also eaten by birds and other insects.

Other research elsewhere has shown the link between microplastics and human health.

Through feeding, the transfer of microplastics in the environment could go as far as people – who caused the plastic pollution in the first place.

Evidence suggests that microplastics reduce the physiological fitness of animals. This comes through decreased food consumption, weight loss, decreased growth rate, energy depletion and susceptibility to other harmful substances. Human health could similarly be at risk on account of microplastic ingestion.

Microplastics can be retained for a longer time at the higher trophic levels where humans belong, thereby predisposing humans to serious health hazards.

Case for a plastic bags ban

A ban on plastic bags would curb the plastic pollution in Nigeria. There are alternatives to the use of plastic bags, for instance, bags made from banana stalks, coconut, palm leaf, cassava flour and chicken feathers. Unlike plastic bags, which could persist in the environments for over a century, bags made from these organic materials decompose readily in a manner that does not pose a health risk to the environment.

For a long while, the call to mitigate plastic pollution was not heeded in Nigeria. Recently, the House of Representatives passed a bill banning plastic bags. But this is yet to be implemented as the president has not assented to it.

A study in the European Union indicates that a ban on single-use plastics could reduce marine plastic pollution by about 5.5%.

It is about time Nigeria treated plastic pollution as a national emergency, considering its implications for human health and the ecological integrity of aquatic ecosystems. An approach that puts people at the centre of the issue has been suggested as one way to convince local communities to preserve the integrity of the environment.

Perhaps this approach could help restore plastic-laden aquatic ecosystems and preserve the pristine ones.

Emmanuel O. Akindele, Senior Lecturer, Obafemi Awolowo University

This article is republished from The Conversation under a Creative Commons license. Read the original article.