The number of oil and gas wells drilled within central Canada and central USA has continued to rise, with an average of 50,000 new wells per year since 2000. These wells bring economic benefits and expectations of at least a temporary energy security. However, the benefits also come with a downside: the potential loss or degradation of local ecosystems.

Recently, a team of scientists explored this threat, providing the first empirical analysis of the consequences of drilling on our ecosystem. In their new study, high resolution satellite data of vegetation dynamics was combined with industry data and publicly available historical records of oil and gas well locations. The research team also evaluated patterns of land-use change and water use.

The team first investigated changes in the amount of carbon fixed by plants and then accumulated in biomass. Changes in this process were examined because carbon fixation and accumulation are fundamental to the life cycle on Earth.

Analysis revealed that across central North America, oil and gas activity reduced the amount of carbon fixed and accumulated in biomass by ~4.5 Tg of carbon (equivalent to a month of forage for five million animals) or 10 Tg of dry biomass (equivalent to ~6 percent of wheat produced in the region in 2013). The reduction comes largely from the direct removal of vegetation due to construction of the drilling sites and necessary roads. This downward trend will likely persist with continued growth in oil and gas activities.

Wildlife habitat and landscape connectivity are two other major ecosystem functions that the team looked at. They estimated that the land area occupied by oil and gas equipment from 2000-2013 is equivalent to the land area of three Yellowstone National Parks. The takeover of this much land can interfere with migratory pathways, alter wildlife behavior and mortality, and increase the likelihood of a disruptive and invasive species infiltrating the ecosystem.

In addition to land use, water use is also a concern. The hydraulic fracturing technology currently in use requires 8,000 to 50,000 m3 of water per well for the first fracturing; in total, this process used anywhere from 7,187 to 33,903 million m3 for wells drilled across the region from 2000 to 2012. Roughly half of these wells are located in regions that were already water-stressed.

The data paints a clear picture of the current and future consequences of the continued increase in oil and gas activity. Most land-use decision making is too focused to result in a truly comprehensive assessment of ecological trade-offs and economic benefit. It is now more important than ever that key decision-makers and scientists team up to ensure the most accurate information is used to shape the policies dealing with delicate water/energy/food balances.

While the data tells a clear story, only integration of the data into land-use planning and policy across many scales will allow us to ensure that damage to the ecosystem is minimized.

Science, 2015. DOI: 10.1126/science.aaa4785 (About DOIs).