Thank you very much for your comment and perspectives. I appreciate your interest in the topic of water footprints.
In your comment you raise the question of why a product should be produced with more water than is necessary. You suggest also that any excess water could be allocated to other uses. While these statements seem appealing at first glance, the issues usually are a bit more complex than your statements indicate. Generally, there is not a single volume of water that represents the amount "actually necessary" to produce a good or service. Water is one input, among many. Producers must evaluate the incremental costs and gains from each input, while considering interactions between inputs. For example, water, nutrients, and pesticides interact in complex ways in the production of crops. Higher yields generally require greater use of inputs. One might wish to reduce the amount of water applied to a crop field, but that effort might require more energy (in the form of implementing drip or sprinkler irrigation) or more labor (in the form of more intensive water management), and it might result in a yield reduction. Society also might be concerned about the relative, incremental impacts and opportunity costs of inputs such as water, energy, nutrients, pesticides, and machinery. It is not sufficient or helpful at the farm-level, or from society's perspective, to focus on just one input, even one as important as water.
You are right that Spain has called for the use of water footprints in assessing water management in river basins. Water footprints seem compelling to many policy makers. Yet, Spain's interest does not demonstrate that water footprints are appropriate or helpful. I describe some of the policy shortcomings of the water footprint approach, with particular emphasis on Spain, in the following review essay:
Wichelns, D., 2010. Virtual Water and Water Footprints: Policy Relevant or Simply Descriptive? Review Essay: Garrido, A., Llamas, M.R., Varela-Ortega, C., Novo, P., RodrÃguez-Casado, R., Aldaya, M.M., 2010. Water Footprint and Virtual Water Trade in Spain: Policy Implications (New York, Springer). Intl. Journal of Water Resources Development, 26(4), 689-695.
You suggest correctly also that the Netherlands is considering the use of water footprints. In fact, the Netherlands Environmental Assessment Agency published a report very recently, in which they conclude the following:
"The water footprint indicator has been effectively used as a wake-up call to raise awareness among the general public, businesses and governments about the global scale of water appropriation. Even so, as these water volumes hardly reflect environmental impact, the water footprint indicator is unsuitable to be used for goal-setting, policy-making, monitoring and evaluation, in relation to sustainability."
You mention in your comments that the Water Footprint Assessment Manual calls for environmental, social, and economic analysis to complement the calculation of water footprints. Certainly, those aspects are important. Yet, they cannot be analyzed and evaluated as easily or as quickly as water footprints can be calculated. Thus, while many authors call for deeper analysis, they do not provide it. They simply publish estimates of water footprints of one or more agricultural or industrial activities. I have critiqued the Water Footprint Assessment Manual in the following article:
Wichelns, D., 2011. Assessing Water Footprints Will Not Be Helpful in Improving Water Management or Ensuring Food Security. Review Essay: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M., Mekonnen, M., 2011. The Water Footprint Assessment Manual: Setting the Global Standard (London, Earthscan). Intl. Journal of Water Resources Development, 27(3), 607-619.
You suggest also that water footprints take water balance into account, and that earlier measures of water use have not done this. I am not sure this is the case. Water footprints simply are estimates of the amount of water used in production and processing. Most - if not all - of the estimated water footprints do not include any information pertaining to water balance. By contrast, numerous reports and journal articles have examined water balance using well-established and time-tested concepts that are well-founded in the science of hydrology and water management. The International Water Management Institute (www.iwmi.org) is a very good source of articles and reports describing water balance calculations.
Perhaps more importantly, no estimates of water footprints contain any information regarding the opportunity cost or scarcity value of water used in production and processing. Such information is critically important in determining the optimal allocation and use of water resources. Lacking such information, we cannot use water footprints to determine appropriate policies or strategies regarding water management.
Hello Nicolas,
Thank you very much for your comment and perspectives. I appreciate your interest in the topic of water footprints.
In your comment you raise the question of why a product should be produced with more water than is necessary. You suggest also that any excess water could be allocated to other uses. While these statements seem appealing at first glance, the issues usually are a bit more complex than your statements indicate. Generally, there is not a single volume of water that represents the amount "actually necessary" to produce a good or service. Water is one input, among many. Producers must evaluate the incremental costs and gains from each input, while considering interactions between inputs. For example, water, nutrients, and pesticides interact in complex ways in the production of crops. Higher yields generally require greater use of inputs. One might wish to reduce the amount of water applied to a crop field, but that effort might require more energy (in the form of implementing drip or sprinkler irrigation) or more labor (in the form of more intensive water management), and it might result in a yield reduction. Society also might be concerned about the relative, incremental impacts and opportunity costs of inputs such as water, energy, nutrients, pesticides, and machinery. It is not sufficient or helpful at the farm-level, or from society's perspective, to focus on just one input, even one as important as water.
You are right that Spain has called for the use of water footprints in assessing water management in river basins. Water footprints seem compelling to many policy makers. Yet, Spain's interest does not demonstrate that water footprints are appropriate or helpful. I describe some of the policy shortcomings of the water footprint approach, with particular emphasis on Spain, in the following review essay:
Wichelns, D., 2010. Virtual Water and Water Footprints: Policy Relevant or Simply Descriptive? Review Essay: Garrido, A., Llamas, M.R., Varela-Ortega, C., Novo, P., RodrÃguez-Casado, R., Aldaya, M.M., 2010. Water Footprint and Virtual Water Trade in Spain: Policy Implications (New York, Springer). Intl. Journal of Water Resources Development, 26(4), 689-695.
You suggest correctly also that the Netherlands is considering the use of water footprints. In fact, the Netherlands Environmental Assessment Agency published a report very recently, in which they conclude the following:
"The water footprint indicator has been effectively used as a wake-up call to raise awareness among the general public, businesses and governments about the global scale of water appropriation. Even so, as these water volumes hardly reflect environmental impact, the water footprint indicator is unsuitable to be used for goal-setting, policy-making, monitoring and evaluation, in relation to sustainability."
The full report of the Netherlands Environmental Assessment Agency is available at: www.waterfootprint.org/Reports/Witmer-Cleij-2012.pdf.
You mention in your comments that the Water Footprint Assessment Manual calls for environmental, social, and economic analysis to complement the calculation of water footprints. Certainly, those aspects are important. Yet, they cannot be analyzed and evaluated as easily or as quickly as water footprints can be calculated. Thus, while many authors call for deeper analysis, they do not provide it. They simply publish estimates of water footprints of one or more agricultural or industrial activities. I have critiqued the Water Footprint Assessment Manual in the following article:
Wichelns, D., 2011. Assessing Water Footprints Will Not Be Helpful in Improving Water Management or Ensuring Food Security. Review Essay: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M., Mekonnen, M., 2011. The Water Footprint Assessment Manual: Setting the Global Standard (London, Earthscan). Intl. Journal of Water Resources Development, 27(3), 607-619.
You suggest also that water footprints take water balance into account, and that earlier measures of water use have not done this. I am not sure this is the case. Water footprints simply are estimates of the amount of water used in production and processing. Most - if not all - of the estimated water footprints do not include any information pertaining to water balance. By contrast, numerous reports and journal articles have examined water balance using well-established and time-tested concepts that are well-founded in the science of hydrology and water management. The International Water Management Institute (www.iwmi.org) is a very good source of articles and reports describing water balance calculations.
Perhaps more importantly, no estimates of water footprints contain any information regarding the opportunity cost or scarcity value of water used in production and processing. Such information is critically important in determining the optimal allocation and use of water resources. Lacking such information, we cannot use water footprints to determine appropriate policies or strategies regarding water management.
Thank you again for your thoughtful comments.