We are Dr Katherine Collett and Brian O'Callaghan and climate researchers from Oxford University focusing on tackling the final 25% of Greenhouse Gas Emissions. Ask us anything!

You suggest 'Considering semi-desert and challenging land for growing plant feedstocks - doesn't that just shift the resource burden into a water problem, eg as seen in California and areas of the Middle East?

Totally agree with the premise here - we must not, and cannot afford to, solve one problem by exacerbating another. If any new solution introduces its own challenges, these must be adequately addressed before any attempts to implement. As such, the types of crops being considered for semi-desert regions are those with low water requirements. If policymakers (or anyone else) were to suggest growing plant feedstocks in these environments at scale, their environmental (and economic review) would need to ensure that water requirements could be adequately met without risking other proximate ecosystems and industries. - Brian

When we discuss using semi-desert and agriculturally challenging lands, we suggest growing plants there that don't require resources un-natural to the area. Instead, we look at plants that require minimal rain fall, or plants that are able to grow in lands with high salinity. These species will be able to grow in these regions, with minimal intervention - some of them will regrow naturally when harvested. These crops would be able to provide a feedstock of sustainably carbon without competing with agricultural land, or requiring large shipments of water. These species are under-investigated but hold the promise of opening up great opportunities to use more land. - Katherine

And why focus on the last 25% of emissions instead of the 80%, which we are still a very long way from tackling?

Getting down to zero requires dealing with all emissions. We (researchers, policy makers, me + Katie) spend most of our time tackling the 80% of emissions that we do know how to deal with (energy, transport, heating), but at some point we're going to have to get on to the harder parts too. These 'harder parts' or 'the final 25%' are those sectors in which we don’t currently know how to economically transition from high-emissions production. The development pathways for these technologies can be long, and that's why we're calling for investment in R&D and market incentives now. Late action in these sectors could lead to undue economic shocks and unnecessary displacement of workers. Investing early allows for a controlled, efficient, and accelerated transition in which inequalities are reduced rather than exacerbated. It also increases the chances that we’ll actually meet our targets. - Brian

You're right that there is still significant work that needs to be done on 80% of emissions we are already tackling. But the premise of this Series is that technological solutions for this 80% exist and significant funding and effort has gone in to commercialising these solutions and rolling them out. Although it may be a difficult transition in these sectors still, it is underway. For the Final 25% of emissions discussed within this Series, the solutions are not yet know, they are underfunded and often neglected. In our rush against the clock, we cannot afford to wait until we have completed the transition of the initial 80% before we begin considering the final 25. We need to get time on our side so that we are able to develop solutions that are efficient, effective and affordable. We need action from policy-makers, investors and industry today to make sure the solutions we will need in the future are research and developed for us when we need them. - Katherine

Do you see the growing middle class in China as a threat to these ideas since they will, probably, have growing emissions through increased meat eating and travel. So, no matter what we do, on a personal level, our impact will be negligible.

We would describe a growing middle class in China as a reason for why we need low emissions solutions sooner rather than later. This is exactly what our series hopes to do: highlight challenging areas, particularly where growth is likely, and focus on what needs to be done to avoid the emissions associated with this in the future. People can eat as much meat as they want if it comes from cultured animal cells - which is real meat without the emissions; and can fly as much as they need if the plane is powered by green hydrogen, ammonia or batteries. The focus is on the solutions that are needed to allows society to function, without the extreme adverse effects of climate change. - Brian and Katherine

Thank you for all your critical work in this space. I mod the r/circular_economy subreddit and wanted to pose a question along those lines: What role does the transition to a circular economy (as difficult as that is) have in tackling the final 25 percent? Or is CE, based on your research, more of an opportunity for the 80 percent?

Great question. CE is certainly helpful for the Final 25%. Lower waste in both agriculture and industrial materials can significantly reduce emissions, and moreover, reduce the need for virgin feedstocks. When it comes to carbon to make plastic, sustainable virgin feedstocks will need to come from plants, the air and waste instead of petrochemicals. This may make them more expensive and recycling through a circular economy may be the most cost effective mechanism to continue using the products we value so much.
In our report on plastics we find that up to 60% of polymers currently used (by mass) are recyclable, but only 18% are being recycled. More recycling would lead to less use of virgin carbon. And this problem is only getting worse with polymer use growing 4% year on year. - Katherine and Brian

Why are they hard to reach?

For us, ‘hard to reach’ sectors are those where we don’t yet have low emissions alternatives that are economically competitive and don’t compromise quality. Hopefully, in the future, we will have these answers and they will no longer be considered hard to reach. - Brian

What needs to happen for the alternatives to be competitive?

Our reports explore this question for plastics and proteins in particular. Broadly, we need to see (A) the costs of alternatives come down or (B) the costs of current high-emissions options go up. A bonus option for proteins – (C) adjustments in consumer preferences could help.
(A) Research and development is needed to progress technology to commercial readiness. Investment now in R&D could bring the costs of alternatives down significantly over the coming decades (rapid reductions in the price of solar panels and batteries are a good example of that).
(B) Various modes of carbon pricing could push the costs of high-emissions options up. In this case, you would use market mechanisms to put a price on the negative externalities of fossil fuel production (idea being "if you pollute the world, you should pay to clean it up"). This carbon pricing, may encourage heavily polluting industry to re-consider their business models and invest in R&D into sustainable alternatives.
(C) In proteins a lot can also be solved with changed diets. People swapping out some of their meat intake for alternative (still high protein) foods could help. - Brian and Katherine

Why don't you talk about China at all? How does the UK's 1% of global emissions compare to China's 28%? We could all eat insects and it would not make a difference

The challenges and solutions discussed within the reports are global and applicable to China. The reports are not UK-centric. In fact, the technological progress made in countries able to invest can be employed by developing nations to assist with climate compatible growth. It is widely acknowledged that a majority of growth in demand will be from developing economies, such as China, and economically viable and sustainable solutions are needed to meet this demand. These reports focus on solutions that would be applicable globally. - Katherine

Consumers in advanced economies have a much higher emissions impact per person than those in emerging and developing nations. This applies across industries - consumers in advanced economies eat more meat, travel more, and spend more on discretionary items - all of which can have high emissions burdens. This is not to say that we should ignore patterns of consumption in emerging markets and developing nations - quite the contrary.
Perhaps the biggest driver of higher agricultural emissions in coming decades will be a rising middle class in China and India. It is nations like these that most need to embrace technological advances which could allow us to live prosperous lives while also not polluting the world. These potential advances are discussed at length in the report. - Brian

When you say hard-to-reach, don't you really mean 'not a chance', at least where eating insects is concerned? In the first place, isn't there an insect decline anyway, in this country? Second, how are you going to convince people to eat them?

Thanks for the question - we're bringing attention here to sectors that still require cost-competitive solutions, rather than giving the solutions! When we talk about the prospects of insects in our alternative proteins report, it is as one of many options that requires further development.

On your second question - you might be surprised at how easy it is to integrate insect proteins into normal foods – from our experience it’s actually quite tasty or you don’t taste it at all! However, we're not suggesting the whole population need eat insects. There are many forms of alternative protein and people can consume the ones they prefer. Insects come in many forms for consumption and can even be available as a flour for cooking with. As it is such a high-protein option, I am sure that the barrier to many to add a scoop of insect powered into a cake or pancake, may be lower than expected.
Apologies, we weren't sure which country you were referring to and cannot directly comment on insect population declines. What we can say is that insects can easily be "farmed" for consumption, so they would not need to be captured from the wild population. - Katherine and Brian