The Millennium Ecosystem Assessment is an international program designed to provide scientific information concerning the consequences of ecosystem change for human well-being and options for responding to those changes. The recently released reports were the work of many hundreds of natural and social scientists.
Walter Reid, head of the core writing team, spoke at UC, Berkeley Wednesday on the central ideas. The work was anthropocentric: focusing on how behavior with short-term benefits has undermined the longer-term ability of the Earth to nurture us.
Both population and per capita consumption have risen rapidly in the past 50 –100 years. This statement looks more impressive on a graph where you see a more or less constant population for many centuries, then doubling in the last 50 years and still-rapid increasing. Per capita consumption is rising even faster, so that economic growth has increased by 5x since 1950.
There are social justice issues, as poor people depend more on ecosystem services than do the rich – that is, poor people get their fish locally.
Ecosystems provide us food, fresh water, wood and fiber and fuel. They regulate the cimate, floods, disease, and water purification. They provide aesthetic, spiritual, educational, and recreational services.
The direct drivers of change are changes in local land use and cover; species introduction or removal; technology adaptation and use; external inputs such as fertilizer, pest control, and irrigation; harvest and resources consumption; climate change and natural drivers such as evolution and volcanoes.
The MA Synthesis Report highlights four main findings:
* Humans have changed ecosystems more rapidly and extensively in the last 50 years than in any other period. This was done largely to meet rapidly growing demands for food, fresh water, timber, fiber and fuel. More land was converted to cropland in the 30 years after 1950 than in the 150 years between 1700 and 1850. More than half of all the synthetic nitrogen fertilizers, first made in 1913, ever used on the planet has been used since 1985. Experts say that this resulted in a substantial and largely irreversible loss in diversity of life on Earth, with some 10 to 30 percent of the mammal, bird and amphibian species currently threatened with extinction.
* Ecosystem changes that have contributed substantial net gains in human well-being and economic development have been achieved at growing costs in the form of degradation of other services. Only four ecosystem services have been enhanced in the last 50 years: increases in crop, livestock and aquaculture production, and increased carbon sequestration for global climate regulation. Two services – capture fisheries and fresh water – are now well beyond levels that can sustain current, much less future, demands. Experts say that these problems will substantially diminish the benefits for future generations.
* The degradation of ecosystem services could grow significantly worse during the first half of this century and is a barrier to achieving the UN Millennium Development Goals. In all the four plausible futures explored by the scientists, they project progress in eliminating hunger, but at far slower rates than needed to halve number of people suffering from hunger by 2015. Experts warn that changes in ecosystems such as deforestation influence the abundance of human pathogens such as malaria and cholera, as well as the risk of emergence of new diseases. Malaria, for example, accounts for 11 percent of the disease burden in Africa and had it been eliminated 35 years ago, the continent’s gross domestic product would have increased by $100 billion.
* The challenge of reversing the degradation of ecosystems while meeting increasing demands can be met under some scenarios involving significant policy and institutional changes. However, these changes will be large and are not currently under way. The report mentions options that exist to conserve or enhance ecosystem services that reduce negative trade-offs or that will positively impact other services. Protection of natural forests, for example, not only conserves wildlife but also supplies fresh water and reduces carbon emissions.
