Climate mortality by the numbers

While the content in this post is somewhat dated by blogosphere standards, I feel it’s important to address the reluctance of the scientific community to quantify the impacts of climate change on human mortality.  Certainly the issue has received more attention this year in both the media and global institutional frameworks (this years WHO World Health Day’s theme was protecting health from climate change).  However, to date, we do not have a concrete number  on just how many individuals are impacted.  The World Heath Organization estimates the number to be around 150,000 annually, but this number is based on a single model from a dated study, and is largely considered a grossly conservative first estimate.

When it comes to the issue of climate change, there is general scientific consensus that global warming is a direct result of an increase in the levels of CO2 in our atmosphere, which is of course a direct result of human behavior.  We have the quantified data to prove it.  Sadly, the impact climate change is having on human mortality is not so cut and dry.   A recent report by the Global Humanitarian Forum suggested that more than 300,000 deaths are already caused by global warming each year, with nearly twice that number possible by 2030.

Alas, the report has been largely dismissed by the scientific community as statistically inaccurate, based on shaky data at best.  Roger Pielke, Jr., an expert on climate policy, called the report a methodological embarrassment, largely due to it’s inability to distinguish between deaths due to climate change and deaths due to population growth and economic expansion.   Andrew C. Revkin from the blog Dot Earth has written an excellent overview of this debate, which this post is largely based on.

This is the problem with reductionist science; It tries to break down complicated and interconnected systems to their individual parts, simply to prove a point.  It only makes sense that when one earth system is pushed out of whack, others should follow.  We see this in nature, in the positive feedback mechanisms of the melting polar ice caps and the shifting of the arctic treeline.  Human beings depend on their natural environmental for survival.  Surely when their environment changes survival strategies must change.  This is evolution at work.  Adapt or die.

We know that climate change-related events are killing people, yet there is no comprehensive global monitoring program to document the lives lost due to climate change. There is no official climate-change body count.  The  I.P.C.C. released the following summary of the anticipated health impacts of climate change on human mortality:

Projected climate-change-related exposures are likely to affect the health status of millions of people, particularly those with low adaptive capacity, through:

• increases in malnutrition and consequent disorders, with implications for child growth and development;
• increased deaths, disease and injury due to heat waves, floods, storms, fires and droughts;
• the increased burden of diarrheal disease;
• the increased frequency of cardio-respiratory diseases due to higher concentrations of ground-level ozone related to climate change; and,
• the altered spatial distribution of some infectious disease vectors.
Climate change is expected to have some mixed effects, such as a decrease or increase in the range and transmission potential of malaria in Africa.

Studies in temperate areas have shown that climate change is projected to bring some benefits, such as fewer deaths from cold exposure. Over all it is expected that these benefits will be outweighed by the negative health effects of rising temperatures worldwide, especially in developing countries.

The balance of positive and negative health impacts will vary from one location to another, and will alter over time as temperatures continue to rise. Critically important will be factors that directly shape the health of populations such as education, health care, public health initiatives and infrastructure and economic development.

Do we still need a concrete number for climate related mortality’s?   Yes and no.

No, because common sense already tells us it must be the case, and empathy for the human condition should be enough to motivate action immediately.

Yes, because unfortunately the effects of climate change will have a disproportionate impact on developing economies.  And numbers, regardless of their basis in reductionist science, may be what’s needed to truly motivate policy change and hold carbon emitters accountable.