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Wellness Corner June 2015 - Climate Change and Human Health - by Dr. Gary Pace


 Climate Change and Human Health

by Dr. Gary Pace

The impact of climate change is starting to be felt on a visceral level—no snow in the Sierras, an epic drought, devastating declines in polar bear populations, etc. Yet, how will these monumental ecosystem shifts affect human health?

A recent conference highlighted local county efforts to adapt to the coming changes (see April 8, Press Democrat). This gathering was reportedly one of the first of its kind in the country. Fortunately, we live in an area where leadership recognizes the threat and is starting to prepare. 

The Science 

The scientific consensus now holds that human activity is leading to a rise in carbon dioxide in the atmosphere, which in turn, contributes to climate instability. Shifts of this magnitude in such a short period of time have not been seen previously. Climate deniers are no longer considered to be offering serious arguments. Generally, it is understood that they want to prevent changes in our energy sectors and economy, and they then bend the facts to back up their agenda. Similar techniques were used by the tobacco industry to raise questions about the health risks of cigarettes.

Scientists feel that a safe level of CO2 in the atmosphere is 350 ppm. Keeping things at this level will allow life to continue evolving much as it has been for thousands of years. Unfortunately, levels recently passed 400 ppm and are rising quickly. Even if we make drastic changes now, the momentum of CO2 increases from our industrial society will continue. 

One very important question that has supreme relevance for humans is, ‘What changes are we likely to see if the temperature rises 2 degrees vs. 4 degrees vs. higher?’ These are different trajectories that can be affected by choices that we make as a society now. If we keep on the current trajectory, we will likely exceed a 4-degree elevation in the next 50 years, which some scientists feel will be the end of modern civilization due to the Earth’s inability to support large populations. If we make drastic cuts in emissions soon, we would still see a rise of 2 degrees, and there will be significant changes in lifestyle, but not catastrophic. Most likely, we will muster up some ability to change things, but not at the level needed—causing a 2 to 4 degree rise—and this will result in massive alterations in the climate and ecology, but possibly not cataclysmic. The specific effects will vary by locale.

Projections about Human Health 

Trying to understand the impact of massive climate change on human health is uncharted territory, but it is possibly the most important public health issue facing us at this point.  NASA divides how the environmental shifts that are already in motion will likely affect humans into four general categories:

1) Ocean acidification: will radical alter the oceanic food web.

2) Sea level rise due to melting of the glaciers: will lead to flooding in coastal regions.

3) Changes in species distribution: will affect where we grow food and vector/disease transmission.

4) Redistribution of rainfall: some areas will get much drier; others will experience tremendous flooding.

So, generally the impacts will be felt in different ways in different locales. Food and water supply are probably the most evident, and the most destabilizing for modern societies. Some analysts speculate that the issues in Syria and other parts of the Middle East are dramatically affected by water shortages and efforts to control water supplies. We can already see these same conflicts emerging in current debates in California between urban and agricultural water use.


At the conference in April, Caitlin Cornwall with the Sonoma Ecology Center applauded the efforts to plan for the coming changes, but she emphasized that “the first thing we need to do is stop making the problem worse” by reducing fossil fuel consumption and keeping more carbon in the ground.  Our ability to cope with the coming changes will certainly be influenced by available resources but will also depend on the magnitude of the disruption. Despite our heavily industrialized society, we are extremely dependent on the natural world.

Next month, we will explore what the experts are anticipating for Sonoma County.