Science and Technology Research News (EUA)

Human Activities Have Already Damaged 75% of Earth’s Surface

Publicado em 17 abril 2018

Less than 25% of Earth’s surface remains free from substantial impacts of human activities. The proportion is set to fall to a mere 10% or less by 2050 according to projections produced by the Intergovernmental Science-Policy Platform on Biodiversity & Ecosystem Services (IPBES).

“Only some regions in the poles, deserts and the most inaccessible parts of the tropical forests remain intact,” said South African scholar Robert Scholes, co-chair of the Worldwide Land Degradation and Restoration Assessment Report launched by IPBES on March 26, 2018, in Medellin, Colombia.

The full report and a Summary for Policymakers (SPM) were approved by the 129 state members of IPBES during the 6th session of its Plenary, held on March 17-24.

According to the report, more than 1.5 billion hectares of natural ecosystems had been converted to croplands by 2014. Croplands and pastures now cover more than a third of Earth’s land surface. Recent clearance of forests, grasslands and wetlands has been “concentrated in some of the most species-rich ecosystems on the planet”, the document stresses.

Scholes said degradation can be defined as the many processes that lead to a steady decline in biodiversity and ecosystem functions or services in terrestrial and associated aquatic ecosystems. “It’s when a region’s capacity to sustain life, both human and non-human, decreases persistently,” he explained.

The report says unsustainable expansion of areas dedicated to cropping and livestock production is one of the main causes of the problem, which will be exacerbated by growing demand for food and biofuels. It forecasts that pesticide and fertilizer use will double by 2050.

“Excessive use of these chemical products contaminates not only the soil but also aquatic systems and eventually affects coastal areas. There are hundreds of dead areas in regions like the Gulf of Mexico, and this is happening because of the way we manage land. So it’s also a matter of water security and coastal conservation,” said Robert Watson, Chair of IPBES.

Another important factor that has contributed to ecosystem degradation, according to the scientists who drafted the IPBES report, is high-consumption lifestyles in more developed economies, combined with rising consumption in developing and emerging economies.

Combating the problem, they write, must include a shift toward more-sustainable diets with more plant-based foods, less animal protein, and greater concern for the methods used to produce food and other consumer goods.

“We’re not telling people to stop eating meat, we’re asking them to look at how it’s produced, and above all to put an end to food waste,” Watson said. “Today, 35% to 40% of the food produced in the developed countries is wasted.”

According to Luca Montanarella (Italy), co-chair of the report with Scholes, communication work is required to help people who live in urban areas reconnect with the land that feeds them.

“We expect the solution to problems like this one to come from outside, but we have our own responsibility as consumers,” he said. “We’re willing to pay high prices for smartphones and computers, but we want food to be cheap. We don’t notice the impact of our food choices because it often occurs far away from us.”

Land degradation is a problem that needs to be solved locally but in a global context, according to Montanarella. According to Scholes, government subsidies to farmers tend to drive unsustainable production growth by enabling them to take more risks.

“It’s possible to increase production without encroaching on natural areas and without using excessive amounts of chemicals,” Scholes said. “Intensification is a large part of the answer, but so is improving land use management practices: nutrient cycling is an example.”

Brazil is in a favorable position to deal with these issues, he added, because in recent years, it has strengthened its scientific research capabilities and also because it has specialists who are able to advise on the best solutions.

“There’s a political clamor for an end to deforestation and to the destruction of wetlands,” Scholes said. “We have an opportunity to start doing things better. There’s room in the market for this. People will increasingly ask whether the goods they buy from Brazil are good or bad” from an environmental standpoint.

Watson acknowledged that biofuels, soybeans and beef are locomotives for the Brazilian economy and that these land-based commodities are valuable to many other countries. “The challenge is to produce them more sustainably and implement best practices,” he said. “There’s a smarter way to do this. It would be a major contribution from Brazil.”

Three faces of the same problem

According to the IPBES report, land degradation through human activities is undermining the wellbeing of at least 3.2 billion people, or more than two-fifths of humanity. This is one of the main drivers of migration, alongside conflicts between communities and the impoverishment of populations, in Watson’s view.

“Degradation of Earth’s land surface through human activities is pushing the planet toward a sixth mass species extinction,” Scholes warned.

Watson added that land degradation, biodiversity loss and climate change are three different faces of the same central challenge. They intensify each other and cannot be tackled in isolation.

The IPBES report finds that land degradation is a major contributor to climate change via both greenhouse gas emissions resulting from deforestation and the release of carbon previously stored in the soil. It estimates annual global emissions of up to 4.4 billion metric tons of CO2 due to land degradation alone between 2000 and 2009.

“Given the importance of soil’s carbon absorption and storage functions, the avoidance, reduction and reversal of land degradation could provide more than a third of the most cost-effective greenhouse gas mitigation activities needed by 2030 to keep global warming under the 2 °C threshold targeted in the Paris Agreement on climate change, increase food and water security, and contribute to the avoidance of conflict and migration”, the report says.

The report also assesses completed and ongoing land restoration processes. Scholes explained that restoration as used in the report means any intentional initiative to accelerate the recovery of degraded ecosystems.

“We made a distinction between restoration and rehabilitation,” he said. “Rehabilitation means initiatives aimed at recovering some of the land’s critical functions and creating the conditions for it possibly to be restored, but returning it to what it was before degradation may not be possible in many places.”

According to Scholes, restoration of degraded agricultural land, for example, may entail returning the soil to its original quality and integrating crop, livestock and forestry systems.

Successful responses in wetlands include control of pollution sources and reflooding areas damaged by draining. In urban areas, the key options for action include spatial planning, replanting with native species, the development of “green infrastructure” such as parks and riverways, remediation of contaminated and sealed soils (e.g., under asphalt), wastewater treatment, and river channel restoration.

The report says solving the problem requires integrating the agricultural, forestry, energy, water, infrastructure and service agendas, along with coordinating policy between different ministries to encourage simultaneously more sustainable practices for the production and consumption of land-based commodities.

On average, the benefits of land restoration are ten times higher than the costs, according to the report.

“Implementing the right actions to combat land degradation can transform the lives of millions of people across the planet, but this will become more difficult and more costly the longer we take to act,” Watson said.

The Brazilian case

According to Carlos Alfredo Joly, coordinator of the FAPESP Research Program on Biodiversity Characterization, Conservation, Restoration & Sustainable Use (BIOTA-FAPESP) and of the Brazilian Platform on Biodiversity & Ecosystem Services (BPBES), degradation is present in all Brazilian biomes and regions but it is more intense where human occupation is oldest, such as in the Atlantic Rainforest, for example.

According to data from the Brazilian Environment Ministry’s Forestry Department (DFlor/SBF/MMA), the country has 200 million hectares of degraded land.

Successful cases of restoration can also be found in Brazil, Joly said. One of the oldest dates from the nineteenth century in the Imperial period.

“The restoration of Tijuca Forest in the city of Rio de Janeiro was ordered by Emperor Dom Pedro II, as recommended by José Bonifácio de Andrada e Silva, to reclaim and protect the water sources that supplied the city. Pedro ordered compulsory purchase of areas held by farmers and landed gentry on the slopes of the mountain ridge that divides the city in two with the aim of restoring the forest, which even in the nineteenth century was almost entirely occupied by farms, pasture and coffee plantations. Few tourists who visit Tijuca National Park today are aware they’re in a restored area,” Joly said.

A contemporary example is the ongoing Atlantic Rainforest Restoration Pact, in which BIOTA-FAPESP is participating through researchers such as Ricardo Ribeiro Rodrigues and Pedro Brancalion.

Data from BIOTA also served as a basis for a mandatory guidelines issued by the São Paulo State Department of the Environment to regulate environmental restoration in the region.

Rodrigues and Brancalion, both members of BIOTA and BPBES, are among the Brazilians who belong to the team of scientists that wrote the report just launched by IPBES, as is Jean Paul Metzger. Other contributors include Marina Morais Monteiro (Federal University of Goiás), Geraldo Wilson Fernandes (Federal University of Minas Gerais), Simone Athayde (University of Florida, USA), and Daniel Luis Mascia Vieira, a researcher at the Brazilian Agricultural Research Corporation (EMBRAPA).

To produce the report, more than 100 leading experts from 45 countries drew on 3,000 information sources including scientific papers, government documents, and indigenous and local knowledge sources.

“The text underwent a thorough peer review and was improved by more 7,300 comments from external reviewers,” said IPBES Executive Secretary Anne Larigauderie. “In addition, the Summary for Policymakers was widely discussed with representatives of state members of IPBES. The purpose of this debate was to enhance the report’s relevance to policymakers.”

Source : By Karina Toledo, in Medellin | Agência FAPESP