It’s no secret that the developed-world’s demand for timber, soybean, beef, palm oil, tobacco, cocoa, coffee and cotton degrades tropical forests. However, evidence shows that deforestation – driven by commodities demand – increases malaria risk in tropical regions. ‘Deforestation has broad, global consequences, but we’re discovering the immediate local consequences on human health,’ says Teevrat Garg, Assistant Professor of Economics, University of California.

Researchers at Stanford University demonstrated last year that a ten per cent reduction in forest cover in the Amazon can increase malaria incidences by 3.3 per cent. Each square kilometre of Amazonian deforestation, they found, could result in 27 new malaria cases. Now, researchers at the University of Sydney have calculated the annual malaria risk attributable to deforestation, which they call ‘deforestationimplicated malaria risk’. They found that the highest risk is in Nigeria, with 5.98 million cases of deforestation-implicated malaria in 2015; then Tanzania, with 5.66 million cases; followed by Uganda, with 5.49 million cases.

Timber, soybean, beef, palm oil, tobacco, cocoa, coffee, cotton – all have supply chains that are in-part dependent on deforestation for primary production. New research is showing that demand from high-income countries could be increasing malaria risk by driving deforestation

There are a multitude of reasons for this link: firstly, forest loss increases penetration of sunlight below the canopy, expediting the growth of mosquito larvae in the soil; secondly, biodiversity loss reduces the number of species that prey on mosquito larvae and adults; third, the influx of labour pushes people into tropical rainforests, where mosquitoes are abundant. ‘Deforestation occurs in remote areas where medical facilities are restricted, and often by poor migrant workers, with limited healthcare access,’ says Teevrat Garg from the University of California, an expert in the intersection of environmental and development economics.

The Sydney team crossed the ‘deforestation-implicated malaria risk’ with supply chain data from commodities trading, to see how demand for commodities may be increasing malaria risk. They found that around 20 per cent of the malaria risk in the world’s deforestation hotspots may be associated with international trade of cash crops such as timber, soybean, palm oil, tobacco, cocoa, coffee and cotton.

Inequality exacerbates the problem. Low-value crops are processed into high-value commodities by more developed countries and companies, but those companies are shielded from the associated health costs. In 2015, $6 billion worth of raw tobacco was exported out of malaria-affected countries, a sum turned into $20 billion worth of processed tobacco, sold out of Europe and North America. ‘There’s a human health cost associated with environmental degradation, so that should be considered as an economic cost as well,’ says Garg.

The researchers offer a range of solutions, from companies engaging more in supply-chain management, to NGOs and governments providing sustainable production training for small-scale farmers. Another option would be to introduce a new certification scheme in which companies that manage to smooth-out the economic and health inequalities of their supply chains could advertise as such. You may have bought fair-trade chocolate, organic produce, or dolphin-safe tuna – if certification proves to be effective, ‘non-malaria–implicated’ products could also hit the shelves.