Tree planting may be less effective than previously thought

A recent article in New Scientist suggests that tree planting may be 15 - 30% less effective in combatting climate change than previously thought.

A Sheffield University study looked at other effects than raw CO2 absorbtion and found some of these may reduce the net benefit. Forest cover can absorb more sunlight than the ground cover it replaces with a warming effect. And chemicals released by trees (the “smell of the forest”) can react with other chemicals which would otherwise absorb methane, and react with oxides of nitrogen to produce ozone - both ozone and methane being greenhouse gasses, and ozone negatively affects crops and can kill trees in sufficient concentrations.

The authors of the study say they haven’t considered all the possible effects and that the whole picture is extemely complicated, but the take-away seems to be that whilst tree planting is absolutely worthwhile, it’s got to be in concert with every other means at our disposal for reducing global warming. And that, of course, includes repair and reuse to combat over-production, over consumption and depletion of basic raw materials.

Talking of which, a hot topic seems to be how to get the message across that recycling is no bettter than a last resort. I’ve recently started working in a small way with Herts County Council Environment and Waste Dept. They simply send their waste electricals and electronics to a recycling contractor. Which immediately raises several questions in my mind.

Ferrous metals, copper and aluminium can perhaps be recycled fairly effectively, but what is the quality of the output? I guess not nearly good enough for the manufacture of high quality steels, aluminium alloys or electrical grade copper. And what is the energy input needed?

What about rare earths, gold, gallium (used in LEDs) and other critical raw materials? These will constitute a small fraction of every tonne of waste sent for recycling. Does anyone even attempt to recover these? And again, at what cost?

Two key metrics for each raw material would be interesting and instructive to research:

  1. What percentage of the total consumption (a) is, (b) realistically could be replaced by recycled product? In a truly circular economy this would be 100%.

  2. What is the energy cost of refining the raw material from waste as a percentage of the energy cost of mining, transport and refining new raw material? If this is greater tha 100% then it’s only worthwhile for scarce raw materials, and for them, the carbon footprint may be significant.

I recently wrote to my MP urging him to support the Repair and Reuse declaration, and got a very feeble response, essentially saying we’ve got WEEE - what’s the problem? We need basic data to counter this attitude. And anyway, what are the compliance levels with WEEE?


Thanks Philip, interesting stuff. I’m glad they note all the other benefits of forestation. It sounds like this would be one to file under the general inadequacy of carbon capture alone as a strategy. As you mention, reduction of unnecessary production and consumption (by those currently over-producing and over-consuming) is more important. And repair and reuse is a key part of that.

I don’t know the answers to your specific questions on material recovery, but can point at some interesting resources. Maybe others will be able to chip in with some specific answers :slight_smile:

  • Even before recovery of materials, our waste composition analysis recently showed that much sent for recycling is in perfect working order already!
  • Specifically on material recovery, our podcast with Oliver Franklin-Wallis might be a good starting point to dive into the topic of waste streams and where things ultimately end up:

On critical raw materials, our podcast with @Jessika_Richter might be of interest:

I believe how to react to this common responses like this might have been covered in our recent webinar (recording in the link below). And @Fiona_Dear might have some thoughts?


Interesting stuff Philip. I have been dealing with Hertfordshire CC on unrelated issues and are of the opinion (judged by their frankly shocking behaviour across multiple departments) that they are teetering on the brink of total failure.

My experience (as an electronics manufacturer) is that WEEE is an absolute bare minimum, box-ticking exercise. Certainly our annual financial contribution was minimal and hard to imagine it would do anything significant to offset the impact of the goods. In basic terms we had to make a financial contribution for the KG’s of product we imported. There was no recognition for repairability or sustainability of the products what so ever.

As (we here) all know recycling should be the last (not first) resort for anything repairable. I have tried in vain to find real data regarding recycling. It does seem no-one wants to talk about the dirty secret. Where are the studies talking about holistic environmental impact of a tv in a skip. It goes so far beyond the carbon cost of producing a new tv. The resource, chemicals, water and energy to turn complex electronics back in to base materials are rarely viable, and only economical where there is gold to be harvested and data to be cleaned (as a paid service).

The mainstream politicians have stood behind (so-called) recycling centres for so long now as an answer. My informal research shows most people I know feel good as long as they throw their old device in the skip.

We are on a mid-term journey to change attitudes towards repair, and educate that most recycling of consumer electronics is just (in reality) landfill depositories. This may sound like a sensationalist statement but the lack of credible information to the contrary is conspicuous by its absence.

I would speculate we are on a 10-20 year journey to reverse the attitudes of the masses towards not seeing consumer electronics as disposable. Manufacturers, politicians, campaigners all will contribute.

When it comes to consumer electronics, society has been sold the vision of the newest and cheapest. We are just at the beginning of reversing that vision. I imagine we are at ‘peak un-repairability’ right now.

I have this conversation with so many otherwise educated people, I am met with as many blank faces (this does not compute) as understanding ones.


Fascinating topics, thanks for starting this Philip!

On the issue of attitudes towards recycling, I’ve been interested in Keep Britain Tidy’s research over the last year or two.

Last year, they published a report examining how recycling is often seen as the best option for unwanted or broken products, despite it being an inefficient solution and near the bottom of the waste hierarchy:

Interestingly, they also found that for many people, the term ‘recycling’ is actually synonymous with more desirable practices, such as reuse, repair, upcycling and so on.

So in a more recent report, they looked at how to help shift the public’s understanding, moving from a focus on recycling to waste prevention, and released a new version of the waste hierarchy:

More here:


And check out our recent podcast interview with Keep Britain Tidy:

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I noticed a couple of interesting snippets on this in a recent article from Fairphone (which, in general, is on the topic of avoiding recycling, preferring reduce/reuse):

For non-Fairphones that have reached their end-of-life, we extract the precious raw materials inside them.

In the video in the article, they state:

…we will make sure every last bit of usable materials is recycled in the most effective way.

So apparently Fairphone attempt to recover them - but I don’t know at what cost. :slight_smile: They might provide this info somewhere.

Also check out the linked video on recycling electronics (specifically batteries) to recoup some of the raw materials on our Materials Matter page: