Climate Change and the threat to Whale Conservation

by Pieter Folkens

Email: animalbytes AT
7 Jun 1996

Michael Perry attributed (by Reuter's) the following to IWC Chairman Peter Bridgewater in a recent MARMAM posting:

"Global climate change, pollution and the hole in the ozone layer are greater risks to the world's whale populations than whaling."

The statement may simply serve to muddy the debate over the resumption of commercial whaling. Nevertheless, the statement in and of itself is dangerous, if not insidious, on two levels--scientific veracity and the opportunity it presents to distract from other important issues.

I submit that pollution is a most serious and fundamental problem to the health of the world's ecosystems, marine and otherwise. Lumping global warming and general climate change within the purview of the whaling debate is unwise. The climate question is so full of unsupportable scientific inuendos that critics can easily attack the weakness of that argument sufficiently to delay attention to the truly serious issues of pollution and abundance which directly impact the recovery and general health of major whale populations. Like predators on the Serengeti, critics will zero-in on the weakest parts.

This statement attributed to Chairman Bridgewater underscores my point:

"Climate change also posed a risk to whales, particularly in Antarctica, a major whale sanctuary. Ozone depletion over the Antarctic could expose whales to damaging solar radiation, which could impact on future whale stocks."

The problems with that statement are numerous beginning with the obvious. Solar radiation is fundamentally necessary for whales. Every year as Earth orbits the sun, a period begins in which *solar radiation* significantly increases. It's called summer. Solar radiation gets the food pyramid started. Without it, carbon-based life forms have no source of energy. (I apologize to all who got a "C" or better in high school biology and already new that.) A narrow band of solar radiation--ultra violet rays--has been shown to have a detrimental effect on some life forms, but it has yet to be demonstrated that an increase in UV radiation has any impact on animals which spend 96% or more of their life underwater at a depth sufficient to filter out most light, including UV radiation.

Additionally, the most recent report on the ozone hole suggests the hole is actually shrinking. Do we know for sure that a fluctuation in the ozone at the poles is not a natural process occurring over many millenia?

During the approximately 50+ million years of Cetacean evolution, whales have experienced at least two significant periods of global warmth much more profound than that which we are currently experiencing. Numerous global temperature oscillations occurred in between with a half dozen warming trends occurring just in the past 10,000 years, each more significant than our current state. We are now in just another relatively minor warming trend. (It has warmed less in the last 4,000 years than it did in the preceeding 2,000 years.)

Big deal. So how did cetaceans do in warm periods anyway?

Referring to an overview of cetacean and oceanic history by Fordyce, The late Oligocene warming trend began with "explosive rediation of odontocetes and mysticetes -- diversity high at species and family level," and ended with a global thermal maximum in the early Miocene and a "high diversity of family-level archaic odontocetes."

Glacial-interglacial/temperate-tropical oscillations apparently contribute to cetacan diversity and speciation. Some tropical species (such as Tursiops and Stenella longirostris) have nearly complete intergrades between very different forms. A significant climate change may genetically isolate some stocks leading to spearate species. This happened before and there is nothing to suggest it won't happen again--except, of course the Environmental Investigation Agency which is declaring the alarm of mass cetacean die-offs due to warm weather.

Our world was warmer about a thousand years ago than it is now, but it cooled quite a bit into the 16th century when the current warming trend kicked in. Are Chairman Bridgewater and the EIA suggesting that the last 400 years of warming had a greater detrimental effect on cetaceans than commercial whaling during the same period?

I admit that global warming will alter the picture,

but it won't end the movie. But pollution--especially in regards to the effects on propagation of basic prey species--is scary.

We cannot afford to make outlandish statements intended to incite a reaction because, once analyzed, credibility is lost and concern for the real issues is distracted. Speakers to the issues must use precise words supported by clear, or at least compelling evidence. The IWC needs to concentrate on developing reliable MSY figures, consider the effects of pollution, and diminish its attention to the slow, but inevitable climate oscillations.

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