The news about Pacific salmon is often confusing. Are stocks in crisis - or not? The short story is that some hatchery stocks are booming, some wild stocks are fine, and far too many unique and irreplaceable stocks - from Alaska to California, are hovering on the edge of extinction.

Clearcut logging destroys forested spawning streams, industrial effluent still pours into rivers and urban development means building parking lots on fish streams. The agribusiness industry, overfishing of endangered stocks, dams and the construction of marinas on top of fragile estuaries add to the damage. Pacific salmon are under siege.

One of the most serious, and least talked about, risks is the danger posed by global warming. But increasing research is beginning to put the gravity of the threat in perspective. Pacific salmon could meet an end in thousands of streams if governments around the world do not act now to reduce fossil fuel use and commit to reductions in greenhouse gas emissions.

From Alaska's Bristol Bay, through the fishing towns of British Columbia to the California coast people depend on salmon. Jobs - and cultures - relove around the annual return. If the streams are too hot, the salmon will vanish.

A 1992 study by D.A. Levy in the Canadian Technical Report of Fisheries and Aquactic Sciences frames the issues confronting salmon in a warming climate. At writing, the scientists contributing to the report envisioned the following scenarios:

• Global warming will increase water temperatures and decrease water flows during spawning migrations. Result: increased pre-spawning mortality. Salmon will die before reproducing

• Global warming will increase water temperatures during egg incubation. Result: salmon fry will emerge too early, increasing mortality

• Global warming will increase the severity and frequency of winter floods. Result: reduced survival rates of eggs to salmon "fry" or young juveniles.

• Global warming will increase stream and river water temperatures. Result: conditions necessary for salmon survival will be less likely to occur.

• Global warming will alter the timing and volume of stream flow discharges. Result: Reduced capability of streams to support juvenile salmon.

• Global warming will alter conditions in Fraser river system lakes. Result: Lakes will be less suitable as nursery habitat for juvenile sockeye salmon.

• Global warming, and resulting increased water temperatures, will alter the aquatic community as a whole. Result: adverse impacts on salmon populations.

• Global warming will shift the timing of the spring freshet or snow melt into rivers and streams. Result: increased mortality of out-migrating juvenile salmon.

The study by Levy focussed on potential impacts in the Fraser River basin. But all salmon species spend most of their lives in the ocean. More recent research has focussed on oceanic survival and the possible impacts of climate change on salmon at sea. The facts paint a dismal picture.

Projections based on circulation models for the northeast Pacific predict sea surface temperatures may increase by 2 to 4 degrees celcius, and wind speeds will decrease. The combination would impact ocean upwelling of nutrients, born to the surface by the movement of cold waters from deep in the ocean. These nutrients play a critical role in the food chain for ocean-going salmon. The upwelling cold water nutrients support and maintain the zooplankton, a primary food source of salmon. Warmer sea surface temperatures would also mean a loss of ideal ocean habitat for salmon stocks. Salmon depend on cool waters.

Fishermen on the west coast of Vancouver Island are already witnessing another impact of changing ocean temperatures - this time brought about by El Nino. The warm water current has brought with it a population of mackeral -- a fish normally found in more southern ocean areas. The mackeral's arrival coincided with the out- migration of juvenile endangered chinook salmon. The voracious mackeral consumed chinook at a frightening rate. A more lasting change in ocean temperatures, brought about by climate change, could lead to a permanent stock of mackeral in B.C. waters, with devastating consequences for Pacific salmon.

In their paper "Effects of Climate Change on Coastal Systems in B.C. and Yukon", Beckman et.al. highlight another risk global warming poses for salmon survival. The authors note that "....increases in precipitation will wash increased amounts of organic material through watersheds and into estuarine areas. Oxygen depletion caused by the decomposition of this material may cause large-scale fish die-offs (Reid and Trexler, 1996) and/or may affect survival rates of (salmon)."

Alaska may be experiencing a taste of what's in store. This season's expected run of millions of Bristol Bay reds (sockeye) is simply not materializing. Initially, speculation revolved around theories that the fish were merely holding offshore. Late June and early July have been unusually warm in the region, and river and estuary temperatures were higher than normal, discouraging the salmon from entering the river.

One short commerical opening for gillnets (inshore driftnets) was held on July 12. Optomism plummeted when over 400 vessels caught an average of only 115 fish each. On July 13, Alaska governor Tony Knowles met with fishermen from the region and was fully briefed on what fishermen are calling "disastrous conditions". The Governor ordered his disaster cabinet to convene, and some compensation for fishermen may be in the offing. There is no discussion of oil company compensation for salmon if it is proven that changing climatic conditions caused this year's run failure.

All the disruptions predicted in a globally changed climate for salmon, fish, shellfish and crustacean populations won't just impact humans. In all likelihood, altered food availability will have a profound impact on black bears, seals, sea-lions, otters, killer whales and eagles to name but a few species.

There is little the bears and whales can do to prevent this potential disaster.

Humans, on the other hand, can take climate change seriously and take action now to prevent the worst impacts of greenhouse gas emissions from destroying ocean life.

No one can say for certain if the salmon will adapt to a changing climate, or die out as a species. But 2,500 of the world's top climate scientists say for certain that climate change is upon us - now. We're about to find out how the salmon fare unless we change course, dramatically and immediately.

Greenpeace concludes:

The threats that global climate change pose to salmon, other fish stocks and ocean ecosystems are numerous and very real. Yet they are only a fraction of the larger, bleaker realities of Earth in a dramatically changing climate. These potentially drastic changes in salmon production serve as a wake up call to governments and individuals alike to take action now. Greenpeace fully supports substantial reductions in greenhouse gas emissions. Greenpeace supports the research concluding that the global climate cannot sustain the risk of industry burning the fossil fuel reserves we have now, therefore further exploration and development should halt immediately. Societies must begin to move from a fossil fuel-based economy to one based on clean, renewable energy sources. Solar and wind power along with energy efficiency measures are available now. These alternatives to fossil fuel have the potential to meet the world's energy needs, create jobs and reduce energy costs while protecting the planet. The barriers to these solutions are not technical but political. Greenpeace is calling on world leaders to drastically reduce fossil- fuel emssions; invest in, and implement, renewable energies and efficiency, and end new oil and gas exploration now.