Why Climate Change is "Bad"

Over the years, some people have criticized me for emphasizing "bad" aspects of global warming rather than "good" aspects.  Since I am very concerned about global warming, this might partially reflect a personal bias.  However, even though there will be some so-called winners with climate change, negative impacts will exceed positive ones, especially if the climate change is abrupt.

Why?  Because our entire society has been built around the climate of the 20th century (and to some degree the climate of the last couple thousand years).  Where we grow crops, how we store and distribute water, where we have built cities, and how we have built infrastructure for resiliency against weather and climate variability are a function of that 20th century climate (and to some degree the climate of the preceding centuries).

Here are some examples.  Water is the agent that delivers most climate impacts and even if there are a few winners with climate change, everyone loses with sea level rise.  Most of the worlds largest urban areas sit in coastal areas. In the United States, more than 50% of the population is near coasts and approximately 3.7 million people living within 1 m elevation of mean high tide (TIDEL).

Source: Strauss et al. (2012)

The challenges in these regions are multifaceted and involve more than the direct effect of inundation by sea level rise.  Coastal erosion and wetland loss increases vulnerability to storm surges.  Saltwater intrusion intrusion into aquifers leads to contamination of drinking water sources.  Etc.

How about National Security?  The Center for Naval Analyses Military Advisory Board, comprised of retired high-level officers and generals fro the armed forces, issued a report this week entitled National Security and the Accelerating Risks of Climate Change.  Again we see here that a shift in the climate is a societal stressor:

"The projected impacts of climate change will be more than threat multipliers; they will serve as catalysts for instability and conflict."

"As the world's population and living standards continue to grow, the projected climate impacts on the nexus of water, food, and energy security become more profound. Fresh water, food, and energy are inextricably linked, and the choices made over how these finite resources will be produced, distributed, and used will have increasing security implications."

"Projected climate change impacts inside the borders of the United States will challenge key elements of our National Power and encumber our homeland security. Of particular concern are climate impacts to our military, infrastructure, economic, and social support systems."

One interesting case study discussed in the report is the impact of sea level rise on the military infrastructure in the Hampton Roads area of Virginia (p. 25), which includes 29 military sites and serves as home for 20% of the U.S. military fleet.  This is a low lying area in which significant adaptation efforts will be needed.

Source: http://www.cna.org/sites/default/files/MAB_2014.pdf

Another region discussed is the Arctic, where the loss of sea ice opens up commercial opportunities but also potential international flash points.

Source: http://www.cna.org/sites/default/files/MAB_2014.pdf

The list goes on and on.  The bottom line here is that change is hard and that's why climate change is "bad." A small shift in climate is perhaps tolerable, but that's looking increasingly unlikely.