MANILA, (SciDev.Net) – Halting or reversing the effects of carbon dioxide and other planet-warming greenhouse gas emissions is best done by using the human footprint to identify key regions where action can be the most cost-effective, says a new study.
According to the study, published last month in Nature, restoring a select 15 per cent of the land converted or degraded by humans could avoid 60 per cent of expected extinctions while sequestering 299 gigatonnes of carbon dioxide, or the equivalent of 30 per cent of the total carbon dioxide increase in the atmosphere since the Industrial Revolution.
According to the World Economic Forum, over half of the land on earth has been converted by human activity.
Restoring 30 per cent of the world’s degraded lands to their natural state could rescue more than 70 per cent of land-based mammals, amphibians and birds at risk of dying out, while soaking up more than 465 billion tons of carbon dioxide.
Most of the priority areas identified are in developing countries and tropical regions, specifically South-East Asia, South Asia, Central and South America as well as West and Central Africa.
“This research is particularly useful for informing strategic decision-making at the level of international policy,” Hawthorne Beyer, a research fellow at University of Queensland in Australia and a co-author of the study, tells SciDev.Net.
“However, achieving restoration in practice requires cooperation among countries to share the costs of restoration, and the development of national and regional programs that encourage land owners to participate in restoration activities and that compensate them for lost revenue — an idea known as ‘payment for ecosystem services’.”
To help identify priority areas, the researchers analysed 2,870 million hectares of ecosystems worldwide that have been converted to farmland between 1992 and 2015. They then assessed the land based on three main motivators — reduction of extinction risk by increasing areas of habitats, sequestration of greenhouse gases, and reduction of impact on agricultural production due to ecosystem restoration. “Not every natural ecosystem will be optimal for climate and biodiversity, and even fewer areas are great for both benefits and not so much for agricultural production simultaneously,” Alvaro Iribarrem, a researcher and professor at the Pontifical Catholic University of Rio de Janeiro, Brazil, and a co-author of the study, tells SciDev.Net.
Further complicating the challenge of identifying priority areas is that “restoration must not impact food production in the context of a growing global population over the coming decades”, adds Beyer
After factoring in the various costs and benefits, the researchers found that restoring forests and wetlands delivers the highest climate and biodiversity benefits, while restoring grasslands and arid ecosystems costs the least.
In particular, 96 per cent of the Caribbean converted lands are in the top 15 per cent of global priorities for biodiversity. Restoring South American and African shrublands, meanwhile, brings important benefits for their unique biodiversity.
“Coordinating restoration efforts across different types of ecosystems will yield the greatest overall benefits,” said Beyer in a handout to journalists.
Douglas Muchoney, head of FAO’s geospatial unit, tells SciDev.Net, that the study is informative and “a jumping off point for more local understanding of local ecologies”. But he stresses that in order to effectively tackle ecosystem restoration, especially as it relates to global challenges, including the SDGs, scientists in general need to treat ecosystems less as an abstraction and more like real places with unique landscapes — and all the complexity that entails.
“We have to anticipate insects and pathogens and people and policy,” he says.
