Over the past weeks and months our climate change series has
told us quite a tale about Earth’s climate system and how it is changing. We’ve
looked at how the green house effect works and what gasses enhance it, what the
parts of the climate system are and how they interact in very basic terms, and
where the carbon comes from and where it goes. We’ve laid the ground work and
now we’re coming to the final chapter of this story, the one in which we find
out what happens next.
And what happens next is a story of degrees. If you have a
chance, read through the Intergovernmental Panel on Climate Change’s 2014
Summary for Policy Makers-it’s available freely online. In it scientists
clearly lay out the risks of various impacts on natural ecosystems and human
societies. The devil is in the details, if global average temperatures increase
only 1 to 2 degrees Celsius, the impacts are “considerable”. If temperatures
increase 4 degrees or more, the risk become high or very high. The different in
temperature increases reflect different emissions scenarios. Two things remain
important to understand, first that under all assessed future scenarios some
risk of adverse impact remains, and second, risks are substantially reduced
under low emissions scenarios. Simply put, no matter what, change is coming,
but we still have some say in just how much change it is.
And what can we anticipate in the coming century (and indeed
it is a hundred year horizon that these predictions mainly look towards)? Where
to start? Risks from climate change are extensions of much of what we see
taking place already. As temperatures increase, so do the risks,
significantly. If we look at the pure
ecosystem impacts, we can anticipate a continued decline in biodiversity and an
increased in extinctions for organisms that can’t adapt and or migrate to
follow shifting favorable climate regions fast enough. Weakened ecosystems then
become vulnerable to additional problems like diseases vectors and invasive
species. These kinds of impacts are what many of us think of when we worry
about climate change, as well we should, but we also need to remember that
intact ecosystems provide vital services like cleaning water and air, and thus,
negative impacts to natural ecosystems also have a negative impact on us. All
of the other risks the IPCC report outlines are ones that directly impact the
functioning of human society. Fresh water resources are projected to decline
due to increased drought, especially in already semi arid areas. At the same
time increased precipitation events are expected, which sounds like a good
thing, except for when the additional inches of rain all fall at once. Then we
have catastrophic flooding, and waste water systems that get overwhelmed,
leading to increased pollution of surface water. High latitude areas may see
increased freshwater resources, which brings up an important point—there can be
effects that have a positive impact. Though, so far the projected negatives
have outweighed the projected positives in virtually all areas of assessment.
Food security is another area where climate change is
expected to negatively impact the human condition. Wheat, corn, rice and soy
are the 4 most widely grown crops world wide, and increasing temperatures are
projected in negatively impact the production of three of them (all but
possibly soy). Decreased crop yields due to heat and water stress are likely to
be the biggest issue, but problems arise with access and distribution as
critical infrastructure is weakened by severe weather events. As annual crops,
intensive breeding may be able to effect adaptation in a relatively short
period of time, and had already yielded some more heat ready, drought tolerant
varieties. The question remains, just how hot will it get? How much heat
tolerance do we need to breed into these staple crops? These are just a couple
of examples of what is coming between now and the end of the 21rst century.
We’ll look at others in the coming weeks.
What we find as we dive increasingly deeper into the thought
exercise that is “preparing for climate change”, is that while science has
identified many negative ecosystem impacts, the things human society needs to
pay attention to are the things that enable our “normal” day to day lives, the
things that are easy to take for granted. Climate change seems very far away
when you hear about a frog in the central American rain forest that has gone extinct,
it’s much closer to home when you go to the sink for a glass of water and
nothing comes out of the tap, just ask the folks in California. We’ve looked at
the science, in this final chapter we’ll be looking at the human part of this
story.
References:
The Summary for Policy Makers (Summary being code for a
document that is still 34 pages long) of the 5th IPCC report on
climate change (2014): http://www.ipcc.ch/pdf/assessment-report/ar5/wg2/ar5_wgII_spm_en.pdf
This document is highly recommended, if still a bit dense.
It contains many excellent graphics that accompany the assessment of risk.
Portland Press Herald (from the Washington Post) on the new
NOAA NASA study: http://www.pressherald.com/2015/01/16/climate-change-milestone-outside-of-maine-2014-sizzled/
From Truthout and Bill Moyers, a shit ton of bad news,: http://billmoyers.com/2015/01/06/climate-disruption-advances-26-percent-mammals-face-extinction/
U S Navy predicts an ice free Arctic in ths summer by next
year +/-3 years…
