Worsening land degradation caused by
human activities is undermining the well-being of two fifths of humanity,
driving species extinctions and intensifying climate change.
It is also a major contributor to
mass human migration and increased conflict, according to the world's first
comprehensive evidence-based assessment of land degradation and
restoration.
The dangers of land degradation,
which cost the equivalent of about 10% of the world's annual gross product in
2010 through the loss of biodiversity and ecosystem services, are detailed for
policymakers, together with a catalogue of corrective options, in the
three-year assessment report by more than 100 leading experts from 45 countries.
Produced by the Intergovernmental
Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the
report was approved at the 6th session of the IPBES Plenary in
Medellín, Colombia. IPBES has 129 State Members.
Providing the best-available
evidence for policymakers to make better-informed decisions, the report draws
on more than 3,000 scientific, Government, indigenous and local knowledge
sources. Extensively peer-reviewed, it was improved by more than 7,300
comments, received from over 200 external reviewers.
Serious Danger to Human Well-being
Rapid expansion and unsustainable
management of croplands and grazing lands is the most extensive global direct
driver of land degradation, causing significant loss of biodiversity and
ecosystem services - food security, water purification, the provision of energy
and other contributions of nature essential to people. This has reached
'critical' levels in many parts of the world, the report says.
"With negative impacts on the
well-being of at least 3.2 billion people, the degradation of the Earth's land
surface through human activities is pushing the planet towards a sixth mass
species extinction," said Prof. Robert Scholes (South Africa), co-chair of
the assessment with Dr. Luca Montanarella (Italy). "Avoiding, reducing and
reversing this problem, and restoring degraded land, is an urgent priority to
protect the biodiversity and ecosystem services vital to all life on Earth and
to ensure human well-being."
"Wetlands have been
particularly hard hit," said Dr. Montanarella. "We have seen losses
of 87% in wetland areas since the start of the modern era - with 54% lost since
1900."
According to the authors, land
degradation manifests in many ways: land abandonment, declining populations of
wild species, loss of soil and soil health, rangelands and fresh water, as well
as deforestation.
Underlying drivers of land
degradation, says the report, are the high-consumption lifestyles in the most
developed economies, combined with rising consumption in developing and
emerging economies. High and rising per capita consumption, amplified by
continued population growth in many parts of the world, can drive unsustainable
levels of agricultural expansion, natural resource and mineral extraction, and
urbanization - typically leading to greater levels of land degradation.
By 2014, more than 1.5 billion
hectares of natural ecosystems had been converted to croplands. Less than 25%
of the Earth's land surface has escaped substantial impacts of human activity -
and by 2050, the IPBES experts estimate this will have fallen to less than
10%.
Crop and grazing lands now cover
more than one third of the Earth´s land surface, with recent clearance of
native habitats, including forests, grasslands and wetlands, being concentrated
in some of the most species-rich ecosystems on the planet.
The report says increasing demand
for food and biofuels will likely lead to continued increase in nutrient and
chemical inputs and a shift towards industrialized livestock production
systems, with pesticide and fertilizer use expected to double by 2050.
Avoidance of further agricultural
expansion into native habitats can be achieved through yield increases on the
existing farmlands, shifts towards less land degrading diets, such as those
with more plant-based foods and less animal protein from unsustainable sources,
and reductions in food loss and waste.
Strong Links to Climate Change
"Through this report, the
global community of experts has delivered a frank and urgent warning, with
clear options to address dire environmental damage," said Sir Robert
Watson, Chair of IPBES.
"Land degradation, biodiversity
loss and climate change are three different faces of the same central
challenge: the increasingly dangerous impact of our choices on the health of
our natural environment. We cannot afford to tackle any one of these three
threats in isolation - they each deserve the highest policy priority and must
be addressed together."
The IPBES report finds that land
degradation is a major contributor to climate change, with deforestation alone
contributing about 10% of all human-induced greenhouse gas emissions. Another
major driver of the changing climate has been the release of carbon previously
stored in the soil, with land degradation between 2000 and 2009 responsible for
annual global emissions of up to 4.4 billion tonnes of CO2.
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.
Projections to 2050
"In just over three decades
from now, an estimated 4 billion people will live in drylands," said Prof.
Scholes. "By then it is likely that land degradation, together with the
closely related problems of climate change, will have forced 50-700 million
people to migrate. Decreasing land productivity also makes societies more
vulnerable to social instability - particularly in dryland areas, where years
with extremely low rainfall have been associated with an increase of up to 45%
in violent conflict."
Dr. Montanarella added: "By
2050, the combination of land degradation and climate change is predicted to
reduce global crop yields by an average of 10%, and by up to 50% in some
regions. In the future, most degradation will occur in Central and South America,
sub-Saharan Africa and Asia - the areas with the most land still remaining that
is suitable for agriculture."
The report also underlines the
challenges that land degradation poses, and the importance of restoration, for
key international development objectives, including the United Nations
Sustainable Development Goals and the Aichi Biodiversity Targets. "The
greatest value of the assessment is the evidence that it provides to decision
makers in Government, business, academia and even at the level of local
communities," said Dr. Anne Larigauderie, Executive Secretary of IPBES.
"With better information, backed by the consensus of the world's leading
experts, we can all make better choices for more effective action."
Options for Land Restoration
The report notes that successful
examples of land restoration are found in every ecosystem, and that many
well-tested practices and techniques, both traditional and modern, can avoid or
reverse degradation.
In croplands, for instance, some of
these include reducing soil loss and improving soil health, the use of salt
tolerant crops, conservation agriculture and integrated crop, livestock and forestry
systems.
In rangelands with traditional
grazing, maintenance of appropriate fire regimes, and the reinstatement or
development of local livestock management practices and institutions have
proven effective.
Successful responses in wetlands
have included control over pollution sources, managing the wetlands as part of
the landscape, and reflooding wetlands damaged by draining.
In urban areas, urban 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 are identified as key options for action.
Opportunities to accelerate action identified
in the report include:
- Improving monitoring, verification systems and baseline
data;
- Coordinating policy between different ministries to
simultaneously encourage more sustainable production and consumption practices
of land-based commodities;
- Eliminating 'perverse incentives' that promote land
degradation and promoting positive incentives that reward sustainable land
management; and
- Integrating the agricultural, forestry, energy, water,
infrastructure and service agendas.
Making the point that existing
multilateral environmental agreements provide a good platform for action to
avoid, reduce and reverse land degradation and promote restoration, the authors
observe, however, that greater commitment and more effective cooperation is
needed at the national and local levels to achieve the goals of zero net land
degradation, no loss of biodiversity and improved human well-being.
Knowledge Gaps
Among the areas identified by the
report as opportunities for further research are:
- The consequences of land degradation on freshwater and
coastal ecosystems, physical and mental health and spiritual well-being,
and infectious disease prevalence and transmission;
- The potential for land degradation to exacerbate
climate change, and land restoration to help both mitigation and
adaptation;
- The linkages between land degradation and restoration
and social, economic and political processes in far-off places; and
- Interactions among land degradation, poverty, climate
change, and the risk of conflict and of involuntary migration.
Environmental and Economic Sense
The report found that higher
employment and other benefits of land restoration often exceed by far the costs
involved. On average, the benefits of restoration are 10 times higher
than the costs (estimated across nine different biomes), and, for regions like
Asia and Africa, the cost of inaction in the face of land degradation is at
least three times higher than the cost of action.
"Fully deploying the toolbox of
proven ways to stop and reverse land degradation is not only vital to ensure
food security, reduce climate change and protect biodiversity," said Dr.
Montanarella, "It's also economically prudent and increasingly
urgent."
Echoing this message, Sir Robert
Watson, said: "Of the many valuable messages in the report, this ranks
among the most important: 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."
