How culling Australia’s feral water buffalo could help tackle climate change

The world’s largest wild population of water buffalo now roams Australia. So is the largest wild herd of camels. We have millions of wild goats and deer. For these introduced species, Australia is a paradise. Lots of vegetation, and not many predators except dingoes, crocodiles and humans.

The problem is that these ruminants break out the powerful greenhouse gas methane from fermenting vegetation in their stomachs. While wild animals produce only an estimated 5% of the methane produced by Australia’s 24 million cattle and 74 million sheep, wild ruminant numbers are soaring.

Buffalo, in particular, are high methane emitters, pumping out methane at about the same rate as cattle. Their numbers have recovered to over 200,000 after earlier culls. Of the world’s animal methane emissions, cattle account for 77% and buffalo for 13%.

At the moment scrap is expensive. But our new research on wild water buffalo in Kakadu shows that could change. If landowners, land managers and governments can claim carbon credits for thinning, it will go from an expense to a profit. In one fell swoop, we can reduce pressure on ecosystems, reduce emissions and add another source of income for those doing the work.

Water buffalo can destroy sensitive wetlands with hard hooves and a love of mud. Shutterstock Are wild ruminants really a big problem?

If you live in a big city, you’re unlikely to ever see the full extent of the problem. But that is changing. Residents in Melbourne and Sydney have become more familiar with wild deer as they spread up and down the Great Dividing Range.

We are more familiar with the damage caused by other introduced species, including foxes, rabbits, rats and cats. Ruminants are a real problem – just not usually in the places where most people live.

These large herbivores are often much heavier than kangaroos and, unlike any native animal, have hard hooves that trample plants, compact soil and increase erosion. They can pollute rivers and lakes, and transmit diseases to farm animals.

Why is it currently difficult to control these animals? The cost. Historically, conservation of wild ruminant numbers was done by sending shooters up in helicopters. Since the 1960s, we have spent billions to control wild ruminants.

Read more: EcoCheck: Australia’s vast, majestic northern savanna needs more care

Despite this, most of these species are more common than ever. How can that be? Once we stop culling, wild animal populations often bounce back very quickly due to their high breeding rates and through migration from neighboring areas where culling has not been undertaken.

For land managers, the scope of the task is often larger than their budget, meaning that wild ruminant control is often put in the “too hard” basket, especially for remote areas. This is where carbon credits can help. As the carbon economy grows, it has begun to change the economics of land use and land management.

Buffalo populations have rebounded from earlier culling programs. Shutterstock Can carbon credits really improve wild ruminant control?

Land managers now have incentives to act to avoid emissions in a way that can be documented and to increase how much carbon their land can absorb in trees, wetlands or soil.

This is because these actions can earn them carbon credits. Each tonne of carbon dioxide equivalent (CO₂-e) kept out of the atmosphere is currently worth around A$30. Credits can be sold to third parties who wish to offset their emissions.

How could land managers create credits by controlling buffalo? We can borrow from the success of farmers and managers across northern Australia’s vast and fire-prone savanna who produce credits by using cooling fires to reduce fuel loads and prevent devastating late-season fires that release large volumes of greenhouse gases.

Early cooling fires in northern Australia could create carbon credits. Shutterstock

At the moment you cannot claim carbon credits for thinning. What if you could? We put this to the test in our research to see if the income from carbon credits would make the outcome self-sustaining.

In short, it would make a huge difference. The income from the sale of carbon credits can far outweigh the cost of waste. Rather than being a major expense, keeping numbers on your property will become a significant source of income.

A water buffalo emits an average of 76 kilograms of methane per year. This is the equivalent of 2.1 tonnes of CO₂. Over a lifetime of 25 years, this is the equivalent of more than 50 tonnes of carbon dioxide.

A rare win-win?

We investigated the wild buffalo population around the South Alligator River in Kakadu National Park and simulated different thinning scenarios. We found that effective control would drastically reduce emissions, reducing up to 913,000 tonnes of CO₂ over 20 years. This would make air thinning very profitable. The net revenue from these avoided emissions would be more than $26 million in credits – after taking out the cost of tailings.

Although more research is needed, we hope that our research shows that the concept is viable. If the culling of high-emitting ruminants such as buffalo earns carbon credits, we believe this will open the door to much better control of wild animals across the Top End.

We can reduce greenhouse gas emissions, open up new revenue streams for landowners and managers, and give regional ecosystems a health boost.

With reduced buffalo pressure, the wetlands and floodplains they turn into mud pits can recover. This, in turn, will help these natural systems to hold their carbon better – and mean that the value of buffalo removal will increase even more. However, at the moment we have not quantified how much extra carbon can be stored.

It is rare to find an approach in land management that benefits both landowners and the environment. Buffalo carbon credits may just be that rare win-win.

Read more: ‘Unacceptable cost’: Savannah burning under Australia’s carbon credit scheme harms human health