Opinion A pledge to do better for world biodiversity

It marked a turning point, then, in the development of international environmental policies and politics. This conference also led to the establishment of a dedicated UN entity, the United Nations Environment Programme (UNEP), based in Nairobi, Kenya. World Environment Day is celebrated on June 5 every year to commemorate that seminal conference, and to recognise the progress made on critical environment issues since then. It also serves as a reminder to gear up for new challenges.

As an annual tradition, this year’s theme for World Environment Day was biodiversity. It is quite remarkable that the recent outbreak of COVID-19 can be linked to the health of ecosystems and human encroachment into wild habitats.

The frequency of disease epidemics affecting human beings has increased in the recent past. In the last 40 years, there have been more than 12,000 instances of outbreaks worldwide, recording more than 40 million individual cases. Increased global travel, trade and connectivity and high-density living are some of the key factors that have contributed to such outbreaks.

However, it is the link to climate change and biodiversity which is the most significant aspect of the COVID-19 crisis. Deforestation has increased steadily over the last few decades and it can be linked to 31 per cent of outbreaks such as Ebola, Zika and the Nipah viruses. Deforestation not only removes the buffer between the human civilisation and wild habitats, it also drives wild animals out of their natural habitats, bringing them closer to human populations — greatly increasing the propensity for zoonotic diseases (those which spread from animals to humans).

Although the challenges, risks and uncertainties due to COVID-19 are all unprecedented, and a huge number of people across the globe are affected, it is also the time to examine the connection between climate change, biodiversity losses and pandemics.

The risk of disease emergence and amplification increases with the intensification of human activities in the vicinity of, or post-encroachment into, natural habitats — enabling pathogens in wildlife reservoirs to spill over to livestock and, eventually, to humans. As habitat and biodiversity loss increases globally, multiple researchers have come to believe that many other disease outbreaks like the COVID-19 pandemic could occur. It has been widely hypothesised that the virus is zoonotic, originating in bats and passing through another animal, possibly a pangolin, before jumping to humans in a market in Wuhan, China.

More than 60 per cent of infectious diseases in humans are caused by pathogens shared with wild or domestic animals. In 2016, the UNEP identified zoonotic diseases as a key emerging issue of global concern. The economic costs of these diseases are staggering and often borne disproportionately by the vulnerable sections of the human population.

A better understanding of the diseases that can be passed on from animals to humans demonstrates how the emergence and re-emergence of zoonotic diseases are closely interlinked with the health of ecosystems. On average, one new infectious disease emerges in humans every four months. While many originate in wildlife, livestock often serves as an epidemiological bridge between wildlife and human infections.

This is especially the case for intensively-reared livestock which are often genetically similar within a herd or flock, and therefore, lack the genetic diversity that provides resilience against pathogens. Whenever human activities or actions encroach on the natural environment and intervene in the existing wild food webs, the risk of exposure to new pathogens increases.

Encroachment on the natural ecosystems for resource exploitation, agricultural activity and human settlements provides opportunities for pathogens to spillover from the wild animals to people. It may be helpful to look at the linkages between biodiversity, climate change and disease outbreaks to have a better understanding about the impacts of human actions on the natural environment, and what steps can be undertaken to slow down the intensity of such crises.

The huge global biodiversity losses now represent a crisis similar in scale and scope to climate change. Biodiversity comprises several levels, starting with the genes, then the individual species, the communities of creatures and, finally, entire ecosystems such as forests, coral reefs, savannah etc. These ecosystems provide a set of conditions where life interplays with the physical environment and the flow of matter and energy occur. These numerous interactions have rendered Earth habitable for billions of years, leading to the evolution of all the species on this planet.

A more philosophical way of viewing biodiversity is this: It represents the knowledge learned by the evolving species over millions of years about how to survive the vastly varying environmental conditions that the Earth has experienced. This knowledge, the inherent logic for survival, imparts a tenacity to the species to adapt or evolve with the changing circumstances. But if the conditions change rapidly without offering the species a chance to cope up, those species are eventually lost forever.

Such irrecoverable loss of species is what’s called extinction. Life on Earth has suffered five mass extinctions of biodiversity in its long history: Caused by massive volcanic eruptions, deep ice ages, meteorite impacts and clashing continents. But it is believed that a sixth mass extinction is already underway. This one is very different, though. It is driven by one single species – human beings.

Humans, and our livestock, now consume 25-40 per cent of the planet’s entire primary production, that is, the energy captured by the plants on which all biodiversity depends. This domination has had an adverse effect on species survival. The number of animals living on Earth has plunged by half since 1970. Many of these creatures fall under the rare, threatened and endangered category, heading towards eventual extinction if stringent actions are not taken to reverse this trend.

Biodiversity, the product of 3.8 billion years of evolution, is therefore under siege. Not only are both marine and terrestrial species experiencing accelerated rates of local and global extinction, but even common species are declining. Human activities have already severely altered 75 per cent of land and 66 per cent of the marine environment. Ecosystems have declined in size and conditions by 47 per cent globally compared to estimated baselines.

Around 25 per cent of assessed plant and animal species are threatened by human actions, with a million species facing extinction — many within decades. One estimate suggests that, by weight, 97 per cent of the world’s vertebrate land animals are now either humans or livestock while only 3 per cent are wild animals.

Climate change associated with global warming pertains to the modification of Earth’s climate system by the addition of greenhouse gases (GHGs) to the atmosphere, either by fossil fuels burning or changes in land cover (deforestation). This is mainly caused by industry, transportation, infrastructure and the agriculture sectors.

A high concentration of GHGs such as CO2, NOx, CH4 enhance the atmospheric absorption of infrared radiation (heat energy), and this trapped heat influences temperature and precipitation patterns. At a planetary level, it causes high mean ocean temperature and sea-level rise, erratic weather phenomena, higher intensity of storms and frequent fire events.

These changes exert pressure on the survival of species as conditions become unfavourable. The combined impact of direct human activities and climate change leads to permanent loss of species. Changes to the climate are reversible, even if it might take centuries to bring down the level of GHGs in our atmosphere. However, once a species becomes extinct, there’s no going back: Since some of those species are unknown to science, there is no good way to estimate the real losses. Globally, approximately 60 per cent of all wildlife species have been lost in the last 50 years, while the number of new infectious diseases has quadrupled in the last 60 years.

The coronavirus crisis holds profound lessons that can help us address climate change and reduce the rate of species loss if we make environmental and economic resiliency core to our recovery planning. The factors that mitigate environmental risks — such as reducing the demands we place on nature by optimising consumption, shortening and localising supply chains, substituting animal proteins with plant proteins, decreasing pollution, etc. — are likely to help in mitigating the risk of pandemics. Ecosystem integrity can help regulate diseases by supporting a diversity of species so that it is more difficult for one pathogen to spread rapidly.

Success against pandemics requires the addressing of the root causes of disease emergence, by curbing human activities that impose extreme stress on the ecosystems and their ability to function. Perhaps, one way is to minimise habitat fragmentation by keeping the natural ecosystems intact as much as possible and avoiding landscape-scale transformative changes.

The ecosystem services on which the health of animals, people and the planet depend, must be restored, safeguarded, and prized. By doing so, we will not only reduce the risk of disease outbreaks but will also apply the brakes on biodiversity losses, slowing down the impacts of climate change.

Bhomia is a scientist, Centre for International Forestry Research (CIFOR), Indonesia, and Kumar is assistant professor CIET, NCERT