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This testimony discusses the harmful impacts of economic growth on the biosphere and the need to change our decision-making process to prioritize the preservation of the environment. It also highlights new information on the limitations of quantitative risk assessments and the importance of addressing exposure to chemical toxins.
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Cumulative Impacts: The Central Problem of Our Time: Testimony before the Clean Air Council April 13, 2011 Documentation is online here: http://goo.gl/9oDIQ Peter Montague, Ph.D. (peter@rachel.org)
For 200 years we have assumed that the biosphere could tolerate an endless series of small environmental insults (harms) that result from the pursuit of economic growth. This is shown in Figure 1, where benefits that are growing without limit are accompanied by costs that are growing without limit.
However, we now know that this view – that the biosphere has a limitless capacity to absorb harm – is not supported by science and is false.
Figure 2 represents the true situation. As benefits grow without limit, and therefore costs grow without limit, it is inevitable that we will, sooner or later, exceed ecosystem limits.
There is abundant evidence that we have already exceeded at least three ecosystem limits: ** CO2 in the atmosphere ** Rate of loss of biodiversity ** Mobilization of phosphorus and reactive nitrogen
Many scientists and many scientific associations are now revealing ecosystem limits that we did not previously appreciate. For example, the 5-year Millennium Ecosystem Assessment studied 24 ecosystems worldwide and found that 14 (60%) are being degraded by human activities.
"We're undermining our ecological capital all around the world," says Robert Watson, chief scientist of the World Bank.(http://goo.gl/Q1JWj)
The Board of Directors of the Millennium Ecosystem Assessment said in releasing the report in 2005: "At the heart of this assessment is a stark warning. Human activity is putting such strain on the natural functions of Earth that the ability of the planet's ecosystems to sustain future generations can no longer be taken for granted.“
As we exceed ecosystem limits, we are running the risk of destroying the biosphere as a suitable place for human habitation. We are risking the loss of our only home in the universe – an infinite loss. No amount of benefits can compensate for an infinite loss.
Therefore, we need to change the way we make decisions We need to change the overarching goal of the human enterprise from promoting economic growth to preserving the integrity of the biosphere.
In recent years we have come to rely on quantitative risk assessment and cost-benefit analysis for regulating chemicals. But new information makes it clear that these tools are not adequate to the task.
Here, in summary form, is some of the new information that drastically reduces the reliability of quantitative risk assessments (and therefore of cost-benefit analyses based on risk assessments).
1. Endocrine disruption Many chemicals can interfere with the endocrine (hormone) system – a biological signaling system that controls growth, development, metabolism, tissue-function, mood, and behavior. Some chemicals can disrupt cell signaling at parts per billion or even parts per trillion.
2. Timing of exposure is critical. The effects of exposures in the womb or shortly after birth can vary dramatically depending on the exact timing of exposure. The dose makes the poison but the timing also makes the poison.
3. Low doses can sometimes be more biologically disruptive than higher doses. The dose-response curve is sometimes shaped like an inverted U. Toxicity testing has always assumed that larger doses are more important than smaller doses.
4. Perinatal exposures can “program” a person for life, thus determining events that will occur during mid-life, such as cancer or other disease. This indicates that the delay between exposure and effect can sometimes be measured in decades.
5. We are exposed constantly to a mixture of chemical toxicants. The assumption of exposure to a single chemical is false. See handout, which summarizes findings by N.J. Department of Environmental Protection in 2003. (available at http://goo.gl/Ef4Q)
6. We all carry a body-burden of chemicals and chemical mixtures, including endocrine-disrupting chemicals. This is further evidence that the assumption of exposure to a single chemical is false.
It is also evidence that another premise of our regulatory system is false. We require pre-market testing for pharmaceuticals because we know humans will be exposed to them. We have exempted industrial chemicals from pre-market testing on the assumption that people will not be exposed.
Now we know that people are constantly exposed to industrial chemicals, so they should be pre-market tested for the same reasons, and in the same ways, that pharmaceuticals are tested.
7. Mixtures can be biologically active We now know that mixtures of chemicals, each present at “insignificant” levels, can combine to produce biologically-significant effects.
8. Epigenetics Epigenetics provides a new understanding of inheritable harm. Non-mutagenic chemicals can cause inheritable changes. “You are what your grandmother ate.”
Recommendations: • Focus not on risk reduction but on exposure reduction. • Eliminate persistent, bioaccumulative chemicals. • Based on screening tools, eliminate emission sources from vulnerable and/or impacted communities.
