Trees to the res­cue

Lesotho Times - - Feedback - An­dreas Wil­son-späth

“Stop wor­ry­ing about cli­mate change al­ready! Some clever en­gi­neer or science bof­fin will come up with a tech­no­log­i­cal so­lu­tion the prob­lem well be­fore we burn the planet to a crisp.”

that’s what some of my friends say when I men­tion global warm­ing and its likely con­se­quences.

Among the sup­posed sil­ver bul­lets that will end the cri­sis are so-called low, zero or neg­a­tive emis­sions tech­nolo­gies (for ex­am­ple ways to re­move and store the CO2 gen­er­ated by coal-fired power plants) and geo-en­gi­neer­ing (large-scale meth­ods of tam­ing the cli­mate, for in­stance by strip­ping CO2 out of the at­mos­phere in bulk or shield­ing the earth’s sur­face from so­lar ra­di­a­tion).

If you, like my friends, have got your hopes pinned on these, I’ve got some bad news for you.

Hu­mans have been un­in­ten­tion­ally prac­tic­ing geo-en­gi­neer­ing for cen­turies, pump­ing all man­ner of pol­lu­tion into the en­vi­ron­ment with­out know­ing the im­pact of these ac­tions.

turns out it’s much harder to de­lib­er­ately fix the re­sult­ing prob­lems than it was to ac­ci­den­tally cause them to be­gin with.

Like a var­sity stu­dent faced with the messy af­ter­math of an epic house party, we’re still in the process of dis­cov­er­ing this tru­ism.

In what is per­haps the most com­pre­hen­sive as­sess­ment of geo-en­gi­neer­ing op­tions to date, a group of ex­perts work­ing un­der the aus­pices of the US Na­tional Acad­emy of Sciences re­cently pub­lished two re­ports that pour cold wa­ter on any hopes for a quick and easy tech­nofix.

Here are some of the key find­ings: — While some pro­posed geo-en­gi­neer­ing meth­ods may be of some use in the fu­ture, they are not ready for de­ploy­ment yet and will never be fix-it-all so­lu­tions to cli­mate change.

We still know way too lit­tle about their ef­fec­tive­ness and a lot more re­search, in­clud­ing smallscale, out­door ex­per­i­men­ta­tion, is nec­es­sary. — Most of the pro­posed tech­niques are pro­hib­i­tively ex­pen­sive and many come with con­sid­er­able risks of detri­men­tal side ef­fects and “unan­tic­i­pated, un­man­age­able and re­gret­table con­se­quences”.

The au­thors of the re­ports warn that us­ing geo-en­gi­neer­ing to fid­dle with the global cli­mate on the ba­sis of our cur­rent scien- tific knowl­edge would be “ir­ra­tional and ir­re­spon­si­ble”.

A work­ing paper pub­lished by re­searchers at the Univer­sity of Ox­ford’s Smith School of En­ter­prise and the En­vi­ron­ment comes to very sim­i­lar con­clu­sions, sug­gest­ing that geo-en­gi­neer­ing and neg­a­tive emis­sions tech­nolo­gies may only reach some de­gree of ma­tu­rity and ef­fec­tive­ness by 2050.

But it’s not all doom and gloom. The Ox­ford sci­en­tists point out that our most ef­fi­cient, cost-ef­fec­tive, sim­ple and ap­pro­pri­ate op­tion for se­ques­ter­ing car­bon from the at­mos­phere is rather well es­tab­lished: planting trees.

they es­ti­mate that a hectare of for­est can trap around 3.7 tonnes of Co2 ev­ery year at a cost (less than $100 per tonne) that beats all of the pro­posed high-tech al­ter­na­tives.

In ad­di­tion, planting trees comes with a num­ber of bonus ecosys­tem benefits, in­clud­ing the pro­vi­sion of wildlife habi­tat, the preven­tion of ero­sion and im­proved soil qual­ity.

The US Na­tional Acad­emy of Sciences re­ports con­cur: re­for­esta­tion is the cheap­est and most read­ily avail­able route to take at this point in time.

So here’s to all the tree-hug­gers who work hard to pre­vent de­for­esta­tion, the tree-planters who toil equally hard to bol­ster the world’s tree pop­u­la­tion, and, of course, to the eco-war­riors who en­cour­age us to re­duce global green­house gas emis­sions in the first place.

Planting trees comes with a num­ber of bonus ecosys­tem benefits in­clud­ing the pro­vi­sion of wildlife habi­tat and preven­tion of soil ero­sion.

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