Our Common Threat — Planetary Health is Public Health

Common Thread
3 min readApr 22, 2021


Today is Earth Day. Compared to other calendar markers, Earth Day feels relatively untouched by the pandemic. It’s a day typically celebrated outdoors, in our minds and hearts, through our deeds and donations. But as we celebrate the second Earth Day under Covid’s reign, the intersections between human health and planetary health are impossible to ignore.

In order to protect human health, we need to protect our planet. Covid is the most devastating reminder of this in recent memory. But it isn’t the only one.

Our global embrace of fossil fuels, deforestation and industrial farming practices have turned our air supply into an enemy, driven our climate to extremes, and made us more vulnerable to death, infection, food insecurity, record-setting natural disasters, and the next era-defining Disease X.

Human behaviour has rapidly accelerated climate change, but can human behaviour slow it?

Yes. In 2018, the Center for Behavior & The Environment at Rare identified 30 actionable steps that individuals and households can take to help reduce our carbon footprint. This list features the usual suspects: composting, ride-sharing, and solar-paneling, alongside a host of land use and agricultural recommendations.

But will cutting ties with the meat industry and converting the single-use plastic obsessives in our lives really make a difference?

Yes and no.

These individual behaviours have the potential to reduce our projected emissions over the next 30 years by over a third. However, that level of mitigation would require a global commitment to uproot our current practices and fully adopt these 30 commandments. You and a couple eager neighbors alone won’t save the planet. But if a collective shift in individual behaviour can make a dent, imagine what an unbending, unanimous change in both systemic and individual behaviour could do.

While the pandemic has taken so much away, it has given the world something incredibly valuable: a moment of revision. In the wake of Covid, governments are reimagining economic, energy and public health policy for a greener future. For the first time, we see climate considerations being made across all sectors. The status quo is slowly turning green.

Animation by Zedem Media

These developments won’t be transformative unless institutions and individuals work in tandem to bring climate to the forefront of everyday decision-making.

At Common Thread, we understand that human behaviour lies at the centre of public and planetary health, these increasingly inextricable domains.

So we’re looking at climate change.

We’re learning from people at the forefront of climate action. We’re listening to the communities most vulnerable to climate change. We’re on the lookout for opportunities to apply our experience in behavioural design to help turn this pivotal moment into sustained momentum towards cleaner, greener pastures. Most of all, we’re here to help. Because if behaviour connects us, it can be what protects us.

We’re spending this Earth Day in admiration of how far we’ve come, and in preparation for all the work we have left to do. We hope you step outside and join us.