Nutrient loading is projected to become an increasingly severe problem, particularly in developing countries. Nutrient loading already has major adverse effects on freshwater ecosystems and coastal regions in both industrial and developing countries.

Comparisons with the rate at which species have disappeared from the planet over a long period of Earth’s history indicate that humans have already increased extinctions levels dramatically. Projections suggest that this rate will take another big leap due to changes over the next 50 years. The bars represent the range of estimates in each case.

From the late 1950s, offshore bottom trawlers began exploiting the deeper part of the stock, leading to a large catch increase and a strong decline in the underlying biomass. Internationally agreed quotas in the early 1970s and, following the declaration by Canada of an Exclusive Fishing Zone in 1977, national quota systems ultimately failed to arrest and reverse the decline.

For all developing countries over the period 1961–99, expansion of harvested land contributed only 29% to growth in crop production versus the contribution of increases in yields, which amounted to 71%; in sub-Saharan Africa, however, yield increases accounted for only 34% of growth in production.

Urban systems are built environments with a high human density. For mapping purposes, the MA uses known human settlements with a population of 5,000 or more, with boundaries delineated by observing persistent night-time lights or by inferring areal extent in the cases where such observations are absent.

While traditional natural resource sectors such as agriculture, forestry, and fisheries are still important in industrial-country economies, the relative economic and political significance of other sectors has grown as a result of the ongoing transition from agricultural to industrial and service economies.

Fishing production dramatically increase through the century peaking in late 1980s. At this time there were major declines in several fish populations in different areas of the world. The catch reported by governments is in some cases adjusted to correct for likely errors in data.

Average annual percentage growth rate of GDP per capita at market prices based on constant local currency. Dollar figures for GDP are converted from domestic currencies using 1995 official exchange rates. GDP is the sum of gross value added by all resident producers in the economy plus any product taxes and minus any subsidies not included in the value of the products.

The MA framework was applied in a wide range of assessments at multiple scales. Particularly for the more local assessments, the framework needed to be adapted to better reflect the needs and concerns of local communities.

International demand for timber may lead to a regional loss of forest cover, which increases flood magnitude along a local stretch of a river. Similarly, the interactions can take place across different time scales. Actions can be taken either to respond to negative changes or to enhance positive changes at almost all points in this framework.

The range of the natural rate of bacterial nitrogen fixation in natural terrestrial ecosystems (excluding fixation in agroecosystems) is shown for comparison. Human activity now produces approximately as much reactive nitrogen as natural processes do on the continents.

There are many linkages between categories of ecosystem services and components of human well-being. They includes indications of the extent to which it is possible for socioeconomic factors to mediate the linkage. For example, if it is possible to purchase a substitute for a degraded ecosystem service, then there is a high potential for mediation.

Eighteen sub-global assessments were approved as components of the Millennium Ecosystem Assessment (MA). These were not designed to provide a scientific sample of any feature of ecosystems or human well-being. Instead, the choice of assessment locations was determined by a combination of interest in undertaking the assessment, interest in using the findings, and availability of resources to undertake the assessment.

Roughly 17% of all the urban land in the United States is located in the 100-year flood zone. Likewise, in Japan about 50% of the population lives on floodplains, which cover only 10% of the land area. In Bangladesh, the percentage of floodprone areas is much higher and inundation of more than half of the country is not uncommon.

The imbalance in long-term water budgets necessitates diversion of surface water or the tapping of groundwater resources. The areas shown with moderate-to-high levels of unsustainable use occur over each continent and are known to be areas of aquifer mining or major water transfer schemes.

A trophic level of an organism is its position in a food chain. Levels are numbered according to how far particular organisms are along the chain from the primary producers, to herbivores, to predators, to carnivores or top carnivores.

Over the past 40 years, globally, intensification of cultivated systems has been the primary source (almost 80%) of increased output. But some countries, predominantly found in sub-Saharan Africa, have had persistently low levels of productivity, and continue to rely on expansion of cultivated area.

The years 1960–2000 have shown a rapid move toward flow stabilization, which has slowed recently in some parts of the world due to the growing social, economic, and environmental concerns surrounding large hydraulic engineering works.

Timber is harvested from forests and plantations and used for a variety of building, manufacturing, fuel, and other needs. Forests (providing fuelwood and charcoal), agricultural crops, and manure all serve as sources of biomass energy.

Access to improved drinking water is estimated by the percentage of the population using the following drinking water sources: household connection, public standpipe, borehole, protected dug well, protected spring, or rainwater collection.