Georgia reader BK alerted me to this article in PHYS.org on a recently understood hero in climate change management. Apparently it’s not just for rainforests anymore.

Savannahs slow climate change

Tropical rainforests have long been considered the Earth’s lungs, sequestering large amounts of carbon dioxide from the atmosphere and thereby slowing down the increasing greenhouse effect and associated human-made climate change. Scientists in a global research project now show that the vast extensions of semi-arid landscapes occupying the transition zone between rainforest and desert dominate the ongoing increase in carbon sequestration by ecosystems globally, as well as large fluctuations between wet and dry years. This is a major rearrangement of planetary functions.

An international study released this week, led by Anders Ahlström, researcher at Lund University and Stanford University, shows that semi-arid ecosystems—savannahs and shrublands—play an extremely important role in controlling carbon sinks and the climate-mitigating ecosystem service they represent.

Tropical rainforests are highly productive, and this means that they take up a lot of carbon dioxide, but rainforests are crowded places with little room to fit in more plants to do more photosynthesis and to store carbon. In addition, the typical moist, hot weather conditions are ideal for growth and do not change much from year to year.

In savannahs it is different. As productivity increases there is room to fit in more trees whose growing biomass provides a sink, or store, for carbon sequestered from the atmosphere. In addition, savannahs spring to life in wetter years, causing large fluctuations in carbon dioxide uptake between wet and dry years. Large enough, Ahlström and colleagues show, to control the amount of carbon dioxide in the atmosphere.

So we need the rain forests, but it’s the returning wetlands that really make a difference. Because of the sudden bloom that comes when a semi-arid region turns green. Gee, are there any semi-arid regions in California? Survey says yes. But what’s the point of discussing it on this website? Because a few well-placed beaver dams could easily trigger this seasonal greening.

CDFW says that California is one of the few places where five major climate types occur in close proximity. Here, the Desert, Cool Interior, Highland, and Steppe climates border a smaller region of Mediterranean climate. Here’s their map of the different zones. You can see that the semi-arid regions stretch across the central valley from Stockton to Bakersfield and everywhere in between,

These dry, warm areas are the places where a tree in standing near the house really make a difference to your family’s comfort. It turns out that a bunch of trees, bushes and foliage on the riparian really matter to the carbon we need to get rid of. So let’s just look at our depredation map and see how California is treating these bounty-makers in semi-arid regions. Something tells me it isn’t going to be good.

Uh-oh lots of dark blue in the modesto region. I guess those semi-arid places got even more arid shortly after those beaver were killed. Oh well, it’s not like Climate change is real or anything. Besides they were interfering with the landscaping.