Climate change, induced by anthropogenic interventions, is the largest current threat to natural World Heritage globally. It is now assessed as highly threatening in 43 percent of sites, compared to 33 percent in 2020.
Published Oct 27, 2025 | 8:00 AM ⚊ Updated Oct 27, 2025 | 8:00 AM
A native grass genetically modified for drought resistance might spread aggressively in arid zones, outcompeting other native flora and altering habitat dynamics.
Synopsis: Chemicalisation of agriculture and natural resources is increasingly inducing genetic changes in species across the board. Many sensitive species have vanished due to the continuous onslaught of pollution, contamination, and intentional spraying of chemicals. Plants, insects, bacteria, and viruses are developing resistance to the intensive and unrelenting use of chemicals, which are able to kill their predators. The wildlife and natural food chain hierarchy has long been imbalanced due to human interventions.
Tens of thousands of species are threatened with extinction as a result of human activities.
According to the new IUCN World Heritage Outlook 4 published in October, climate change is threatening 43 percent of natural World Heritage sites, surpassing all other threats.
As per this report, the second most prevalent threat is the spread of invasive alien species affecting 30 percent of all sites. The report also warns of a sharp rise in the risk from wildlife and plant diseases. In 9 percent of sites there is a high or very high threat posed by pathogens, up from just 2 percent in 2020.
Scientists expect habitat and wildlife destruction to combine with pollution and 2-3°C of warming by 2046-54, leaving 20-60 percent of Earth’s species extinct, but IUCN seems to have ignored the most critical threats.
There are two severe threats that have not received enough attention from IUCN: gene contamination and distortion, and the spread of resistant species.
Chemicalisation of agriculture and natural resources is increasingly inducing genetic changes in species across the board. Many sensitive species have vanished due to the continuous onslaught of pollution, contamination, and intentional spraying of chemicals.
Plants, insects, bacteria, and viruses are developing resistance to the intensive and unrelenting use of chemicals, which are able to kill their predators. The wildlife and natural food chain hierarchy has long been imbalanced due to human interventions.
The world sees the proliferation of single species among previously diverse populations wherever predator numbers have drastically declined, if not disappeared altogether.
Plant resistance often involves genetic changes that enable plants to defend themselves against pathogens, pests, or environmental stress. Plant resistance refers to a plant’s ability to avoid, tolerate, or recover from attacks by pathogens, such as fungi, bacteria, and viruses, or pests, such as insects. This resistance can be natural or introduced through breeding or genetic engineering.
Plant resistance is fundamentally tied to genetics. There are two main types: monogenetic and polygenetic resistance. Genetic change in the form of mutation, gene transfer, epigenetic modifications, or selection can lead to resistance. However, these changes are based on the plant’s natural ability or selections and are most probably within its natural limits.
On the other hand, plant resistance induced by chemicals or other human interventions can be unpredictable and unsafe.
Farmers and scientists breed crops, a process called resistance breeding, with desirable resistance traits to reduce pesticide use and improve yield. Genetic engineering is also used to insert resistance genes, such as Bt genes for insect resistance in cotton and corn, as part of biotechnology.
This kind of induced resistance can pose a future threat to the world heritage of wild plants and other forms of life.
Gene transfer—particularly from genetically modified crops—can contribute to the emergence of super weeds, but it is not the only cause. Herbicide overuse plays a major role. Globally, there are 530 unique cases (species by site of action) of herbicide-resistant weeds, encompassing 272 weed species (155 dicots and 117 monocots) that have evolved resistance to 168 different herbicides from 21 of the 31 known herbicide sites of action.
Many invasive plant species have developed resistance to herbicides, especially in areas where chemical control has been heavily used. Some super weeds can be invasive, but not all.
The terms “super weed” and “invasive weed” refer to different traits, though they can overlap. Invasive species are generally more amenable to developing herbicide resistance than local species, primarily due to their aggressive growth, adaptability, and exposure to repeated chemical control.
The term invasive does not always mean non-native. While many invasive species are introduced from other regions or countries, some invasive species can be native under certain conditions. Native species can become invasive following genetic engineering or prolonged chemical usage, especially when these interventions alter their growth, reproduction, or competitive behaviour.
A native grass genetically modified for drought resistance might spread aggressively in arid zones, outcompeting other native flora and altering habitat dynamics. Repeated use of herbicides or fertilisers can unintentionally favour certain native species.
Over time, this can shift the ecological balance, allowing these native species to become dominant and invasive.
In India, Parthenium hysterophorus—though originally introduced—is now so widespread and chemically resilient that it behaves like a native invasive weed, thriving in disturbed and chemically treated soils.
Invasive behaviour can suppress other native species. Dominant growth may change soil chemistry, water availability, or fire regimes, leading to habitat alteration that affects other dependent animal, bird, and insect species. Genetically modified native plants may interbreed with wild relatives, spreading engineered traits unpredictably.
Climate change, induced by anthropogenic interventions, is the largest current threat to natural World Heritage globally. It is now assessed as highly threatening in 43 percent of sites (117 of the 271), compared to 33 percent in 2020.
Invasive alien species remain the second most prevalent current threat, whilst a surge in wildlife and plant diseases is now affecting nine percent of sites (23 out of 271 sites assessed), up from just two percent (five out of the 252 sites assessed) in 2020.
Diseases such as Ebola virus in primates (Virunga National Park, DRC), white-nose syndrome in bats (Mammoth Cave, USA), chytridiomycosis in amphibians (Tasmanian Wilderness, Australia), avian influenza (Peninsula Valdés, Argentina), and top-dying disease in Sundarbans mangroves (Bangladesh) are impacting ecosystems and threatening keystone species, most probably caused by humans, including tourism.
The report identifies tourism as the third most widespread current threat.
The IUCN report further emphasises that threats from invasive species and diseases are often interconnected and intensified by climate change.
Shifting temperatures and precipitation patterns can enable invasives to spread faster and further and can alter the conditions for pathogens.
Predicting and preventing these cascading impacts due to genetic engineering and chemical usage is critical, not only for ecosystems but also for human health.
(Edited by Dese Gowda)
