All posts by Mariana Clare

PhD Student researching numerical fluid and sediment transport models at Imperial College London

Recycling plastic bags won’t stop climate change

A few months ago I had the privilege of attending the recording of the 70th anniversary of the BBC Radio 4 programme “Any questions?” in the House of Commons (podcast available here) where a panel of guests were asked pre-selected questions by the studio audience. To mark the special occasion and look towards the future of the programme, all the members of the panel and the studio audience were aged under 30. Given this, the first question for the panel was: “Will our generation be the one to finally take decisive action on climate change?”. As a member of the Mathematics of Planet Earth CDT, I was intrigued. The first answers from the panel included an insightful remark from Jordan Stephens, a member of hip-hop duo Rizzlekicks, suggesting the problem is posed incorrectly. He pointed out that people always say we’re saving the planet, but actually the planet will survive and what we’re doing is saving ourselves. The last person to answer the question was Conservative MP Tom Pursglove. His response was to talk about personal responsibility, the need to cut down on litter, and the current government’s policy on cutting the use of plastic bags and micro plastic beads.

Figure 1:  Committee Room 14, the location of the programme and, incidentally, where the results of the Conservative Party no confidence vote concerning Theresa May were announced exactly two months later. Source: Wietze Beukema

To put it in context, this debate came two days after the publication of the IPCC report stating that even if we meet current pledges to reduce carbon dioxide emissions, the world is still heading towards 3°C of warming over pre-industrial levels by 2100. According to the report, to limit warming to 1.5°C (the limit defined in the Paris climate agreement) would require an annual average investment in the energy system of around $2.4 trillion. Hence, it is predominately the energy sector including energy generation and usage in transport and industry (and arguably the agricultural sector) that needs to change. On the other hand, recycling plastic bags or even cutting plastic waste entirely has no real meaningful impact on climate change and it is important to be aware of the differences between the two issues. Plastic waste is clearly a huge environmental issue; just look at the massive plastic islands in the ocean. Animals can get trapped in packaging or die from ingesting plastic. Moreover, it would be unfair not to mention a recent study from the University of Hawaii, which suggests that decaying plastic may result in methane emission into the atmosphere. However, compared to the contribution from burning fossil fuels, that of plastic waste is insignificant.

Figure 2:  A vast mass of plastic stretching for miles in the Caribbean Sea. Source: BBC

By confusing the two issues of plastic waste and climate change, we can think that by solving one, we are also solving the other. In fact, in a recent article in the BBCGuy Singh-Watson, a green campaigner and founder of Riverford Organic Farmers, argued that “the almost religious fervour – of some of our customers in (being) anti-plastic can actually create problems…The biggest environmental challenge facing our planet is climate change – and anything that distracts attention from that is potentially dangerous.” I would argue further that the problem is in fact worse because people think that by reducing their use of plastic, they are also helping to slow down climate change. By coincidence, a week after attending the recording of ‘Any questions?’, I listened to the podcast “Sept Milliards de Voisins” where they discussed the possibility of living without plastic (podcast available here in French). The presenter asked Bruno Tassin, Director of Research at l’Ecole des Ponts Paris-Tech and a specialist in dealing with plastic in the environment, how much plastic waste contributes to climate change. Tassin explained that although plastic usage does result in greenhouse gas emission, this is mainly when the oil to make plastic is extracted and refined. This is a common problem with resources (see a previous article (How renewable are renewables really) on this topic). The fact the presenter asked the question is another example of a respected public figure getting confused between the two separate issues of plastic waste and climate change.

The most concerning aspect of this climate change misconception in the “Any questions?” debate was that it was coming from an MP who is from my generation, and young enough to have been taught about climate change at school. I am not trying to make a political point. The response from the Labour MP on the panel, Danielle Rowley, was a very open meaningless statement that Labour “are committed to being a lot stronger on tackling climate change” without any specific strategy or commitments. I’m sure many MPs across the political spectrum also think that recycling and reducing waste has some impact on climate change. Perhaps more shockingly, some of them, including Graham Stringer MP, a member of the Commons Science and Technology Committee, do not believe that climate change is man-made (see article in the Independent). Whilst this is disheartening, we should use this as motivation to be better informed than those in power, which is not difficult!

To return to the original question, about whether our generation will indeed be the one to take decisive action on climate change, my honest answer would have to be, I hope so but it is by no means certain. Unfortunately, the recent IPCC report emphasises that if we leave it to the next generation, it will be too late. I remain optimistic that, as the people educated about climate change at school begin to take positions of power, they will take more meaningful action. From the admittedly small sample audience present at the “Any questions?” recording, it was clear that my generation care about mitigating climate change. However, in order to do this, it is important that we keep ourselves well informed about the issues and keep our eye on the main goal: reducing greenhouse gas emissions. There are plenty of ways to do this, including many suggested in the recent IPCC report, such as eating less meat, buying a fuel efficient (or electric) car or travelling by train instead of flying. So please, continue to reduce your plastic use, but don’t think this means you are taking action on climate change.

How renewable are renewables really?

Renewables are on the rise. The International Energy Agency (IEA) forecasts global capacity of wind, solar and hydropower will grow 43% in the next five years. Such technologies are called renewable since their source of energy (e.g. sun, wind or flowing water) naturally replenish themselves. This can be contrasted with fossil-fuel generation, whose fuels (e.g. coal or gas) can be depleted and take millions of years to regenerate.

The classification into renewable and non-renewable refers only to the process of electricity generation. Over their whole lifecycle, renewable technologies use resources that can both be depleted and lead to greenhouse gas emissions in their extraction process. Furthermore, they need a lot of them: per unit of electricity, wind turbines require 6-14 times more iron and 11-40 times more copper than fossil fuels. Meeting one quarter of global electricity demand from wind by 2050 would require an additional 1 million onshore and 100,000 offshore wind turbines, and the IEA estimates that decreasing energy related greenhouse gas emissions by 50% doubles the material requirements per unit of electricity. Obtaining the additional materials required may negatively impact the environment in their extraction and in their processing.

Furthermore, renewable energy production requires materials that may be scarce, toxic, or required for domestic electronic devices. An important example is the lithium and cobalt required for lithium ion batteries. The demand for these is expected to grow exponentially because of their use in portable electronics, electric cars and storing renewable electricity (see a previous article on this topic). Both metals are available only in a small number of countries, with cobalt a particular concern; more than half of world supply comes from DR Congo, a country infamous for its political instability and plagued by civil war. The combination of high demand and supply uncertainty has even lead to deep-sea mining pilots, worrying many environmentalists. Clearly, the environmental impacts of a massive renewable transition should be considered carefully — we must be careful that one source of environmental damage (greenhouse gases emissions) is not substituted for another.

Figure 1: Lifecycle greenhouse gas emissions per unit of electricity generated for different renewable and non-renewable energy sources. Source: IPCC, 2011 Special Report on Renewable Energy Sources and Climate Change Mitigation (Chapter 9).

In this backdrop, shrinking renewable technologies’ material requirements is a key priority. Many approaches fall under the age-old mantra Reduce, Reuse, Recycle. One strategy is to design new technologies that require fewer scarce resources. The lithium ion battery is itself an improvement on its lead acid predecessor, and the race to build a new battery, free of lithium and cobalt, is in full swing. Another is to increase the effective lifecycle of existing technologies. As everyone with an old mobile phone recognises, battery performance declines over time, and this is usually the first reason to discard an otherwise working model. The same applies to wind power: the harsh conditions experienced by turbine blades, including lightning strikes, storms and ice, decreases the efficiency of wind turbines 60% in their first 15 years of operation. Replacing blades periodically or making them more resilient lowers material requirements, but comes with considerable technical challenges.

A third option is to recycle materials. The first generation of large-scale renewable projects built in the 1990s are reaching the end of their lifetimes, meaning millions of tonnes of old wind farm and solar panel materials will be decommissioned. Estimates suggest that by 2030, there will be 300,000 tonnes of waste from old wind turbines annually in Europe alone, and most of these parts are made from costly unreformable plastic that cannot be melted down or given a second life. Reusing components both reduces demand for mining and prevents costly materials ending up in landfill sites. Examples include a planned recycling centre in Texas where old wind turbines are cut up and given a second life in composite panels and a French chemical firm building blades from reformable plastic. In the EU, research funding and targeted landfill bans have lead to pilot projects into the recycling of solar panels and batteries. Some of these batteries have even been given second lives in grid-scale storage. However, recent attempts have been slow to get off the ground, and for many of these technologies, mining new materials remains cheaper than recycling. Furthermore, recycled materials typically cannot be reused in renewable technologies again and must be sold to other sectors.

Many of the issues outlined above relate to the fact that these technologies are still in their infancy. Fossil fuel technologies have been the dominant energy source for more than a century, and trillions of dollars have been invested to maximise their efficiencies. If and when such sums start being spent on renewables, technologies are expected to improve significantly. These improvements have already sent the price of renewables plummeting, and they may make the renewable resource question disappear altogether in the future.

Furthermore, despite the hefty material requirements, a study by the Norwegian University of Science and Technology estimates that the planet has enough resources to support the large-scale transition to renewables, and it’s not the case that fossil fuels don’t use any materials for their infrastructure — imagine, for example, the amount of metal and energy required to build on oil rig. In terms of lifecycle greenhouse gas emissions, renewables are a clear improvement on non-renewables (see Figure 1). However, having enough resources for the foreseeable future does not mean this will be the case forever.

Becoming a truly renewable society requires not just the adoption of renewable technologies, but also their improvement. Otherwise, it may be that in solving one sustainability issue, we are creating another.

Adriaan Hilbers – PhD student researching Mathematics of Power Systems at Imperial College London

Mariana Clare – PhD student researching numerical fluid and sediment transport models at Imperial College London