Once we have come to understand the specifics of the environmental state, we can then start developing an integrated story of what is happening to the environment and why. We accomplish that by answering: “What are the Pressures and Drivers that have caused the change to occur?”
Examples of types of drivers and pressures identified in many global environmental assessment reports, such as UNEP’s GEO-4 report on the state of the global environment and the Millennium Ecosystem Assessment of 2005, are provided in Table 6.
• Consumption and production patterns
• Science and technological innovation
• Economic demand, markets and trade
• Institutional and socio-political frameworks
• Distribution patterns.
– agriculture, fisheries and forestry
– transport and housing
– finance and trade
– energy and industry
– security and defence
– science and education
||• Human influence
– land use
– resource extraction
– modification and movement of organisms
The purpose of identifying drivers and pressures is to establish an integrated story of likely causes of the observed changes in the state of the environment. The story starts with identifying a pressure, which is readily identifiable as a cause of the environmental change. For example, sewage discharge from upstream communities represents a pressure causing changes in water quality in a river or coastal bay. A driver behind this particular pressure could be rapid population growth in the upstream communities.
|Figure 8: Growth of agriculture exports
in Canada (NFU 2005)
Drivers and pressures affecting the state of water quality in the Red River
The increases in total nitrogen concentration in the Red River north of Winnipeg are affected by several direct pressures. The entire watershed of the Red River is intensively farmed on both sides of the border between Canada and the United States. Given this land use, there exists a high potential for non-point source nutrient loading via runoff during heavy rainfall and spring melt events.
There also is a major urban centre (the City of Winnipeg) just south of the mouth of Red River at Lake Winnipeg. Pressures on the river from storm water drainage, as well as treated and periodic discharges of untreated sewage add to the pressures resulting from agricultural activities. While Winnipeg is a major centre near the delta of the Red River, there are several towns and cities in the upstream reaches of the river in both Canada and the United States.
|Figure 9: The DPSI Story Sheet.
There also are natural events that directly pressure the river system, including slow biological metabolism during cold winter seasons when temperatures can remain below minus 15 degrees Celsius for weeks or months on end. Most notably, there are frequent floods in the Red River Basin, the most recent of which occurred in 1997, causing damage in excess of US$2 thousand million in the United States and Canada (NRCAN 2006; Wikipedia 2006).
|Figure 10:Analysing drivers, pressures
and states and trends
The drivers of these pressures also can be articulated. In terms of the pressure of nutrient loading from agricultural land, there has been a several-year trend of increasing agricultural exports from the Canadian prairies (Figure 8). Canada’s National Farmer’s Union (NFU) indicates that while Canadian agri-food exports have expanded fivefold since 1979, family farm incomes have declined over the same period (NFU 2005)
See Exercise 5.4.3 a
An integrated story must not stop at understanding the causality chain for just one specific issue. Integrated environmental assessment looks for linkages among environmental issues. A driver or pressure identified for one issue could be having an effect on other environmental issues. This combination of interlinkages was described in Figure 3.
For example, you might have a concern about the state of water quality in a river, and might identify sewage discharge upstream as a direct pressure on this state. In that example, are there other environmental states for which this sewage discharge might be serving as a pressure? It is possible that the discharge affects the state of air quality (e.g., odour) in communities around the sewage discharge. Additionally, the driver of rapid population growth could cause increased agricultural activity, which in turn could cause an increase in deforestation.
See Exercise 5.4.3 b