Where did the water go?

 

I was interested (and somewhat amused) to read that the biggest reforestation project in the world has had some - wait for it - unintended consequences.  Say it ain't so!

China’s massive tree-planting push has long been hailed as a climate win. But new research shows the country’s ambitious effort to slow land degradation, and fight climate change, has also reshaped its water supply in surprising, and sometimes uneven, ways.

When China dramatically expanded forests and restored grasslands under its "Great Green Wall" initiative, it didn’t just change what the land looked like, it changed how water moves between the ground and the atmosphere.

. . .

“They’ve actually increased forest cover by 15% over the last five decades,” [meteorologist Jennifer] Gray explained. “If you think about the amount of moisture that those forests are releasing into the atmosphere, it is just an incredible amount.”

. . .

What surprised researchers most wasn’t that water moved, it was where it ended up. “What’s so remarkable about this study is the scale of it and the unintended consequences,” Gray said. “The rain was distributed in completely different ways and in completely different places.”

The reason lies in the atmosphere itself.

“The atmosphere and the winds can actually transport moisture more than 4,000 miles,” Gray explained. “So if you plant trees in one area that doesn’t mean that that’s exactly where it’s going to rain.”

. . .

That’s why Gray says climate solutions can’t stop at planting trees. “It puts an exclamation mark on the importance of having city planners get involved, water management folks get involved as well,” she said, “so this can be carefully thought out as to where the water is going to be distributed once you do something like this.”

There's more at the link.

This is fascinating to me.  I've never figured out how bureaucrats and political functionaries can dictate to Nature - "We are going to do this, to force you to do that" - without any real understanding of how Nature works, the interplay of forces and influences that mold and shape the world we live in.  It seems ridiculous on the face of it;  what my father would call "farting against thunder".  The power of natural forces is so enormously greater than anything of which we can conceive that it makes fools of the bureaucrats who think that way.  Perhaps this is yet another example of the folly that led to Mao's megalomaniac "Great Leap Forward", which led directly to the "Great Chinese Famine" and caused tens of millions of deaths.

I think it's a laudable ambition to halt desertification by reforestation . . . but just reforesting thousands of square miles doesn't mean they'll be transformed into the microclimate you want them to have.  I'll be watching the progress of similar projects with great interest.  Ethiopia is planting 50 billion trees;  there's the Great Green Wall for the Sahara and the Sahel;  and India has The Great Green Wall of Aravalli.  I wonder if they'll all run into the same problem?

(There's also the colonial-era Great Hedge of India, designed to prevent unwanted border crossing in either direction.  Perhaps the Border Patrol might like to investigate that project?)

Peter