Nexus Notes – climate solutions, activism, coral restoration and more

It's Nexus Notes time!

Welcome to Nexus Notes. These are quick thoughts from me designed to share things I’ve been up to, been reading or just any other random stuff I’ve come across I think you may enjoy for the week.

In this post: reduced food waste as a climate solution, whether climate activism works, large-scale coral restoration feasibility, and tree-planting initiatives around the world.

Location? Have a guess. Answer at the end of the post.

Hi folks!

Hope you’ve had a good Easter break. The weather here in NZ has been atrocious but is coming right now. It’s been a busy and fun time in the Tonkin household with two kids birthdays in a couple of weeks plus easter. Hope you’re all doing well out there. Enjoy some tidbits from the week.

Climate solution I’ve been thinking about

Reduced food wastage

On a global average, per capita food wastage footprint on climate in high income countries is more than double that of low income countries, due to wasteful food distribution and consumption patterns in high income countries. “Source: FAO.

About a third of the world’s food is never eaten. Where it is wasted along the supply chain depends on where you are in the world. In developing nations, it tends to be on farms and during storage. In higher-income regions, food tends to be rejected by retailers and consumers because of imperfections (😡).

Wasted food means wasted energy and resources that went into its production, including water, energy, fertiliser, land and seeds. It also means wasting the energy that went into transport, processing and packaging when it makes it that far along the supply chain

Reducing food waste, then, means reduced need for all of these resources, particularly land, energy and water, but also all of the resources used along the supply chain.

Given the multi-source nature of these wastages, the solutions are diverse, from improving storage and transport systems to, in high-income regions, focusing on systems overhaul in the retail and consumption side of things. The latter may be through public awareness campaigns to change behaviour and attitudes towards food.

Project Drawdown provides a nice overview of this issue here, suggesting up to 102 gigaton of carbon dioxide equivalent could be reduced over the next 30 years.

Paper I’m reading

Thomas-Walters, L., E. G. Scheuch, A. Ong, and M. H. Goldberg. 2025. The impacts of climate activism. Current Opinion in Behavioral Sciences 63:101498. DOI: 10.1016/j.cobeha.2025.101498

Copied from original paper: “Map representing the strength of evidence for linking climate activism to various outcomes based on the literature reviewed here. Note. The strength of evidence is based solely on the literature captured in this review. We balanced the amount, quality, and representativeness of evidence in deciding on the weights to assign to each link. This is somewhat subjective. We have separated mobilization and voting out from individual behavior change as the two types of public behaviors most relevant to climate activism.”

This paper reviewed “50 of the most recent and rigorous studies evaluating the impacts of climate activism”. They found that climate change activism has clear impacts on public opinion and media coverage, and likely impacts voting and politician communication. Although weaker evidence, the paper also suggests there is direct impact on policy and emissions. Currently, research is biased towards USA and Western Europe, so generalisability of the findings is difficult, but highlights the need for more research.

The Conversation piece of the week

Reality check: coral restoration won’t save the world’s reef.

Coral reefs are under attack around the world from a suite of stressors, particularly global warming and marine heatwaves, but also overfishing and pollution. We’ve already lost about half of the global coverage of coral reefs over the past 40 years!

Restoration is certainly an option at helping to return reefs, but the scale of local restoration cannot match the extent of the problem. Even just between 2009 and 2018, 12,000 square km was either lost or degraded. The cost of such restoration is unfortunately untenable.

“Restoring the reefs we’ve already lost around the world could cost up to A$26 trillion.”

As the piece, and associated paper emphasise, coral restoration can be useful at small scales, which can certainly be beneficial to address local needs, including engaging local communities. But it is not feasible to scale up to address global needs. There is no substitute for addressing the root cause of climate change.

Feel-good news of the week

‘It will be beautiful to see our kids grow up with this’: how communities around the world are planting trees.

This is a lovely piece about people around the world taking action and planting trees whose shade they may never sit under. These are true leaders. As you know, I’m a big fan of people who take action for future generations.

Photo location?

Okavango Delta, where wildlife comes to meet on a seasonal basis. In the heart of the Kalahari Desert, seasonal pulses of water bring wildlife from very long distance to congregate and capitalise on seasonal rhythms. Seasonal cycles that support wildlife around the world are at risk. As mentioned last week, we have an exciting paper coming out in the next couple of months that discusses the implications of changing seasonal cycles across the web of life. Stay tuned.

Wishing you all a fun and productive week!

Jono

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