This Week's Post: Climate Change and Biome Shifts

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This Week's Post: Climate Change and Biome Shifts

There are many reasons why global climate change poses significant challenges for humans.  The pages reproduced below are from my hand-lettered textbook Wa-Maka-Skan:  Fundamentals of Wildlife Ecology and Conservation.

Figure 2 on the page below ("Major Biomes of North America") shows the observed link between two major climate features, mean annual precipitation and mean annual temperature, and the occurrence of major vegetational communities.

As our industrial civilization changes the climate, the new temperature and precipitation patterns become less favorable for biomes as they are currently distributed.  Climatologist Stephen Schneider says, 'biomes find themselves stranded in the wrong climate.'   The existing vegetation will die, beginning on the southern and northern edges of its range, and different plant communities will begin to emerge.  Even with rapid climate change, this transition will take hundreds of years in most cases.

These biome shifts have widespread consequences for agriculture, forestry, groundwater recharge, river flow, biodiversity and a host of other taken-for-granted benefits that we receive from a relatively stable Nature. 

Grassland areas become warmer and drier as they shift toward desert communities.  This is important for humanity since our major agricultural regions occur in grassland biomes.  Shifting agriculture northward (in the northern hemisphere) as grasslands migrate north into formerly forested areas is problematic because the forest soils (that developed under forests) are less well-suited for the crops we depend on.

In ecosystems (and even in engineered systems), change is destabilizing. My generalized biome map on the second page shown below will have to be revised in the year 2500.



Environmental Commentary: "Heading for the Cliff"

Here's another page from my sketchbook of graphical visualizations of environmental issues-- climate change again.

The top figure (I) shows humans shifting our living conditions to another state, a warmer environment. The sphere rolling uphill represents the human enterprise heading for conditions for which it is not immediately adapted-- abnormal conditions. And for an operation tailored to normal conditions, abnormal conditions are problematic. This scenario assumes that we immediately stop emitting from any source carbon dioxide that exceeds the Earth's capacity to sequester it. In other words, our net additions of carbon dioxide to the atmosphere are ZERO. This is not likely, despite the fact that we are the most "highly educated" and "technologically advanced" gang of humans ever to have existed.

The lower figure (II), under current conditions of concern and commitment, is a more likely possibility. There is only so far we can push the current array of multicellular organisms (mostly plants, fungi, and animals) into an environment for which they are not adapted. By the way, humans are multicellular organisms.

Of course there are probably more possibilities. Can you think of any?

"Climate warming possibilities" from the sketchbook. © Fred Montague

"Climate warming possibilities" from the sketchbook. © Fred Montague