The Complexities of Climate Change: ongoing studies to determine mankind's impact

The complexity of global warming and its effects are highlighted in journal articles cited by SeaWeb in its latest Marine Science Review (issue #359). The challenge to scientists in determining the long-term effects is how best to correlate a myriad of artificially introduced components that can either increase or even decrease atmospheric and ocean temperatures.

A study in Nature Geoscience examines the complexities behind the El Nino-Southern Oscillation (ENSO) which begins in the tropical Pacific but whose effects extend worldwide. Predicting the frequency and extant of this oscillation has been a challenge even in the best (aka "al naturale") of circumstances. By interjecting man-made factors, the predictability becomes even more difficult. But it is clear that a strong ENSO raises temperatures along the equator, changing wind patterns that impact temperature gradients between surface and deep water layers both at the equator and beyond.

Another study in Nature Geoscience examined issues related to atmospheric aerosols - particles and gases in the atmosphere that have the ability to actually lower temperatures (an extreme example of this would be the extended "winter" that doomed the dinosaurs brought on by ejecta from a meteorite impact). With man-made pollutants, like smog, sometimes both effects - heating and cooling - are at work due to the nature of what is being thrown into the air. This can make it challenging for scientists to determine the end net result and for those who have proposed the use of man-made atmospheric aerosols to moderate temperature, called radiation management, the results are questionable. One fact is known: atmospheric aerosols ultimately weaken the ozone layer, as we had over the Arctic, which increases temperatures.

There were two studies in Toxicon that examined the increase of Ciguatera, a fish poisoning that occurs with the ingestion of algal toxins. As it works its way up the food chain, the effect accumulates and becomes magnified. Human consumption of infected fish can produce some nasty gastrointestinal and even neurological effects. One study, focused on the Caribbean, and showed that the incidence of ciguatera was highest where high and relatively consistent sea surface temperatures (SST) occurred. In contrast, another study in the South Pacific showed that there is a temperature threshold over which ciguatera prevalence is dampened, but determining where and when this dampening effect occurs is challenging due to the oscillation of ocean currents in the area.

And lastly, a study in Climate Policy reminded us all of where the impacts of climate change will fall on human populations. Equatorial, developing countries - in Africa, the Indian subcontinent, Latin America, and small island states - will feel the greatest effects, affecting subsistence-level economies. And this will have to be taken into consideration when establishing international policies. The industrial world, existing in colder latitudes, has produced over 66% of the global greenhouse gases, but its equatorial neighbors will experience over 75% of the effects within this century.

Climate ecology, like many of the natural forces from evolution to the birth of the universe, is an incredibly complex system unto itself. This makes the study and outcomes of man-made intrusions a very difficult one to forecast. But there is no doubt that mankind is having an impact. I receive 20 to 30 summaries on climate change studies each month from SeaWeb - the data is there, the research is ongoing, and the reality of climate change should be a worldwide concern.

This Winter's Extreme Weather: climate change defined by macro-weather patterns

With some extreme winter weather taking place in some parts of the world, discussions about global warming would seem to fall on deaf ears. It can be challenging to gain the attention of a U.S. senator regarding warming ocean temperatures when he or she is shoveling several feet of snow to get to the U.S. capitol!

In United States alone, we have had some flip-flopping of "normal" weather patterns: heavy rains in southern California, record snow levels in the northeast, and a cold snap in Florida that has caused the deaths of over 100 manatees and triggered an extensive coral bleaching event. Even with an unusual warm spell in Vancouver, British Columbia as the Winter Olympics are about to begin, it doesn't sound much like global warming, does it?

However, one must look beyond micro-weather patterns and look at the big picture, at annual or decadal trends, and even longer, to determine what is a natural cycle or an anomaly or a man-made trend.

As an example, NASA's Goddard Institute for Space Studies recently declared 2009 to be the second warmest year on record, next to 2005. This first decade of the 21st century has been the warmest on record, warmer than the previous decade which was the former record holder. With changes in macro-weather patterns over a long period of time, there are disruptions to the typical wind, temperature, and ocean current patterns. In the Pacific Northwest, changing climate conditions are being considered responsible for steadily increasing wave height over the past several decades, posing greater flooding and erosion potential. Ironically, these major weather disruptions can manifest themselves regionally in ways that would seem to run counter to the idea of global warming.

One seasonal weather event that occurs in the Pacific is the El Nino - a change in the usual sea temperature patterns that warms the Pacific and disrupts weather patterns across much of North and South America. Research that has studied the El Nino over several centuries have shown that it has been occurring more frequently, with over 40% of the extreme events taking place in the 20th century, with 30% of those occurring after 1940. There is an El Nino in place right now and is considered the source of much of the current abnormal weather patterns in the North America.

There are some scientists who propose that all of this represents a normal macro-weather pattern, that this is all nature's doing and not man-made. But as research continues, we are beginning to see that the rate of change seems to be much greater than from any other previously recorded or extrapolated natural cycle - another accelerant would appear to be at work here. Hence, the issue of man's impact through CO2 and other greenhouse gas emissions and the use of fossil fuels.

Opponents of global warming have characterized it in various ways, from a natural-occurring event to a massive global conspiracy by maniacal scientists. While I don't buy into the Machiavellian plots, I would propose that if all the research were to ultimately point to a natural shift, I for one would choose not to simply sit back and enjoy the ride, proclaiming there's nothing we can do and watch ecosystems shift and species (including homo sapiens) disappear in many parts of the world. I just can't sit on my hands.

However, having reviewed the continuing stream of research studies, my inclination is that man-made activities have been the primary cause behind climate change. We did it and we can do something about it.

Read SeaWeb article on recent cold temperatures, El Nino, and northeast Pacific wave height.