Assessing the Empirical Basis of the "Biodiversity Crisis"

Assessing the Empirical Basis of the "Biodiversity Crisis"

May 01, 1993

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EXECUTIVE SUMMARY

For several years now, the World Wildlife Fund and other wildlife interest groups have been saying such things as, "Without firing a shot, we may kill one-fifth of all species of life on this planet within the next 10 years." One problem with such assertions is that there is no scientific justification for making them. Based on the most up-to-date published data concerning species loss:

• Known extinction rates are very low;

• It is impossible to estimate even approximately how many unrecorded species may have become extinct;

• We do not know how many species exist, even to within an order of magnitude, and therefore have no basis upon which to assert that we know what percentage is going extinct;

• Relatively few attempts have been made to rigorously assess the likely magnitude of extinction rates.

Edward O. Wilson, the foremost proponent of global efforts to stem the purportedly unsustainable loss of species, says that "the extinction problem" is "absolutely undeniable." Wilson cites "literally hundreds of anecdotal reports" to support his claim. However, the very reason for the scientific method in estimating rates is that anecdotal reports are of little or no value, and often mislead the public and policymakers. Indeed, that's why expensive censuses and other data gathering instruments are employed. However, very little work has been done in this field. A survey of the existing evidence finds the following:

• The estimated extinction rate of known species is about one every four years from 1600 to 1900;

• The estimated rate is about one a year from 1900 to 1979;

• Some scientists have "hazarded a guess" that the extinction rate may now have reached 100 species per year;

• In tum, this guessed upper limit has been used as the basis for projecting that as many as 40,000 species will be dying out annually before the year 2000.

These numbers have the power to frighten the public in a fashion that smaller numbers would not; this, in tum, prompts particular government policies that could not be otherwise justified. Nevertheless, there is no scientific justification for such use of numbers.

The scare about species extinction has been manufactured in complete contradiction to the scientific data. It is truth that is becoming extinct, not species.

The known facts about biodiversity lead to the inevitable conclusions that:

• If something is unknowable at present but knowable in principle, then the appropriate thing to do is to find out;

• At present, some conservation biologists seem more intent on whipping up concern for species loss than they are in documenting the extent of that loss and analyzing the possible ramifications, if any;

• More reliable information about species loss is necessary to guide future policy decisions;

• Future policies to address species loss must include the direct and indirect costs of such policies, including the long-term costs of reduction in economic growth to a community's health.

There is now no prima facie case for any expensive species-safeguarding policy without more extensive analysis. But the question deserves deeper thought, and more careful and wide-ranging analysis, than has been done until now. As children say, just saying so does not make it so.