The world’s nations committed to halving overall threats to biodiversity from pesticides and other highly hazardous chemicals by 2030 at the 15th United Nations Biodiversity Conference in 2022.
But new research finds most countries are trending in the wrong direction when it comes to ecological risks from pesticides, with the UN’s global risk reduction target unlikely to be met without substantial changes to agricultural systems.
In fact, only one country, Chile, is currently on track to meet the UN target of reducing pesticide risk by 50 per cent by 2030, according to recent findings by a team of environmental scientists from German university RPTU Kaiserslautern-Landau, and published in the journal Science.
Pesticide risk in this context is defined as the probability of chemical compounds — including insecticides, herbicides, and fungicides — used to control agricultural pests having adverse effects on species not directly targeted by the pesticides and, thus, on ecosystems more broadly — and ultimately on humans.
To determine global pesticide risk, the study researchers looked at data on pesticide use from 2013 to 2019 in 65 nations that collectively represent nearly 80 per cent of global crop acreage. They then combined these statistics with data on the toxicity of 625 pesticides for eight different species groups, including aquatic invertebrates and plants, fish, pollinating insects, soil organisms, and terrestrial arthropods, plants and vertebrates.
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It is hard to steer or to restructure agricultural systems, but nonetheless, it’s important. We have been entrenched in this agricultural system for decades now.
Jakob Wolfram, environmental scientist, RPTU Kaiserslautern-Landau
This novel analytical approach, dubbed total applied toxicity (TAT), was developed by the RPTU researchers, and was first deployed by the team in a 2021 paper that found the toxicity of insecticides has substantially increased in the US, particularly for aquatic invertebrates and pollinators.
“TAT is basically an expression of the amount of pesticides that are used in terms of their toxicity and not their mass, so that we have a toxicity-weighted use estimate,” explained Ralf Schulz, an ecotoxicologist and professor of environmental sciences at RPTU Kaiserslautern-Landau, and who led the study together with Jakob Wolfram, an environmental scientist and Ph.D. candidate in aquatic ecotoxicology at RPTU.
“The UN, when they decided in the Kunming-Montreal [Global Biodiversity Framework] protocol in December 2022 [to reduce] pesticide risk, didn’t define what they mean by this,” Schulz said. TAT is the result of the RPTU team’s efforts “to come up with simple indicators that can be used to [determine] to what extent countries have really managed to reduce their pesticide risks.” It will be used to track progress toward meeting the 2030 pesticide risk reduction targets going forward (a draft guidance has already been issued by the UN, and will be finalized in June).
The team found that the overall ecological toxicity of pesticides is increasing worldwide, and that just four major agricultural producer countries — Brazil, China, India and the United States — account for more than half of global TAT.
While they determined that pesticide risk in some countries, such as China, Japan and Venezuela, is trending in the right direction, even these nations need to accelerate their efforts in order to meet the 2030 UN target. Other countries, such as Thailand, Denmark, Ecuador and Guatemala, meanwhile, are moving in the wrong direction and must take urgent action to reverse ecological harm from their pesticide use.
The researchers found that the global TAT of most species groups has increased, in particular that of terrestrial arthropods, soil organisms and fish, while only two species groups, aquatic plants and terrestrial vertebrates, were found to have seen declines in applied toxicity. They also discovered that treatment of fruits and vegetables, corn, soybean, cereals and rice account for more than three-fourths of global pesticide toxicity.
Perhaps most importantly, the researchers determined that overall global pesticide risk is dominated by just a few highly toxic chemicals. Focusing reductions on these high-risk chemicals could represent one of the best opportunities for nations to get on track to meeting the 2030 pesticide risk reduction target, they suggest.
“With regard to the countries,” Schulz said, “obviously there are some very important [national] users of pesticides that contribute a lot to the overall TAT. But when you look at the different species groups … very often you see that it’s a handful of pesticides, or probably a dozen pesticides, that are most relevant for the TAT.
“[I]n my view, that is good news because it would probably tell the countries if they know they have a risk, let’s say, for pollinators, then they can look up which pesticides are most responsible for their pollinator risk (for their pollinator TAT) and then … come up with measures [to] handle these kind of pesticides,” he explained.
Nations could, for example, replace these more toxic pesticides with less toxic ones, or change the agricultural system so there’s less need for toxic pesticide use.
Jason Rohr, a professor of biological sciences at the University of Notre Dame in the US, who was not involved in the study, told Mongabay that “This is an exceptionally strong and policy-relevant study because it moves beyond tracking the sheer volume of pesticides used and instead quantifies their toxicity-weighted impact on biodiversity at a global scale.”
He noted that “By integrating pesticide application data with regulatory toxicity thresholds across multiple species groups and countries, the authors provide one of the most comprehensive assessments to date of how agricultural chemicals affect non-target organisms.”
Rohr called the RPTU team’s TAT approach a “key advance” because it shows that, even in cases where overall pesticide use may hold steady or decline, pressures on biodiversity can still increase.
“The finding that global toxicity trends have risen for many taxa between 2013 and 2019, counter to the UN goal of reducing pesticide risk by 50 per cent by 2030, is particularly striking,” he said. “Importantly, the study also identifies geographic variation and highlights that a relatively small number of highly toxic compounds drive a disproportionate share of risk, suggesting clear leverage points for more strategic and effective policy interventions.”
Study co-leader Jakob Wolfram noted that efforts to reduce pesticide risks by 50 per cent could pose a serious challenge to agricultural producers, but the hope is that applying the TAT approach could allow for breakthroughs in conserving biodiversity and reducing pesticide risks without interfering too much with agricultural production and food security.
However, Wolfram stressed that good data is critical to effectively reducing pesticide risk, but that data is very limited at present. “The whole success of guiding these national targets, and also the [2030] global target in the end [depends on] reliable pesticide use data. And even in developed countries, reliable and accurate pesticide use data is rare,” he said.
Wolfram urges a major effort be undertaken to map a “data-driven, science-backed way forward,” so targeted progress can be tracked and informed policy recommendations can be used to implement impactful and successful changes to agricultural systems.
Wolfram cautioned that, due to limited available data, the study’s finding that most nations aren’t on track to meet the 2030 pesticide risk reduction target is based on the research team’s projections. “We rank [nations] based on their current trajectory… And when we’re looking at these trajectories, there is still a lot to do for practically all of the countries.”
But despite these national shortfalls, Wolfram said he and his colleagues are quite optimistic positive change can occur. “The 2030 target that was set is very short notice. It is hard to steer or to restructure agricultural systems, but nonetheless, it’s important. We have been entrenched in this agricultural system for decades now. And that means some substantial change need to happen so that countries move towards the target rather than the many … moving currently away from it.”
This story was published with permission from Mongabay.com.
