In several countries, to slow global warming, many farmers are

Question

In several countries, to slow global warming, many farmers are planting trees on their land because of government incentives. These incentives arose from research indicating that vegetation absorbs carbon dioxide that might otherwise trap heat in the atmosphere. A recent study, however, indicates that trees absorb and store carbon dioxide less effectively than native grasses. Therefore, these incentives are helping to hasten global warming.

The argument requires the assumption that

(A) trees not only absorb carbon dioxide but also emit it
(B) most farmers do not plant any trees on their land unless there is an incentive to do so
(C) land that has been deforested seldom later sustains native grasses
(D) some of the trees planted in response to the incentives are planted where native grasses would otherwise be growing
(E) few if any governments have been interested in promoting the growth of native grasses

Source: LSAT

gmatexam439 · Answer

In several countries, to slow global warming, many farmers are planting trees on their land because of government incentives. These incentives arose from research indicating that vegetation absorbs carbon dioxide that might otherwise trap heat in the atmosphere. A recent study, however, indicates that trees absorb and store carbon dioxide less effectively than native grasses. Therefore, these incentives are helping to hasten global warming.

The argument requires the assumption that

Grass is better than trees when it comes to reducing global warming. Thus, if trees are grown in places where grasses could have been grown, then global warming would increase .

(A) trees not only absorb carbon dioxide but also emit it - This is a fact statement. Irrelevant 
(B) most farmers do not plant any trees on their land unless there is an incentive to do so - This is a fact statement. Irrelevant .
(C) land that has been deforested seldom later sustains native grasses - Deforestation is cutting of trees. Argument at hand is planting of trees. Irrelevant .
(D) some of the trees planted in response to the incentives are planted where native grasses would otherwise be growing - Correct. If trees are grown in places where grass could have been grown, then the planting of trees will fasten the process of global warming .
(E) few if any governments have been interested in promoting the growth of native grasses - Irrelevant .

AMsac123 · Answer

I didnot understand this one. Can someone explain this to me

Sangeeta2018 · Answer

Conclusion: Trees help to hasten GW. Premise: Involves the reasoning for the conclusion by comparing Trees with Native Grasses.

A wrong. Only a fact regrading tree is given. Doesn't give a reason as to why trees are detrimental to native grasses.
B wrong. Conclusion doesn't revolve around Incentives. Out of scope.
C wrong. Argument revolves around planting of trees. Not cutting down of trees.
D correct. Some of the trees planted in response to the incentives are planted where native grasses would otherwise be growing. This says that farmers are planting trees more in the greed of incentive,which if not there,the land would have been occupied by Native grasses. So, the more trees,more it helps in hastening GW.
E wrong. Out of scope.

LucasDinizMiranda · Answer

Can someone better explain why C is wrong ? I do understand that the argument is about planting trees but shouldn't I consider that farms are deforested lands?

Thx in advance

Posted from my mobile device

AshutoshB · Answer

Actually ,author is sayng growing trees would fasten global warming , although we know trees absorbs co2,so we hve to shows how planting trees would fast the globl warmng ,opt D is precise ,thats y C is irrelevant

Hit kudos if u like

Setback · Answer

Conclusion: Therefore, these incentives are helping to  hasten  global warming.

The key term to focus here is 'hasten'.The argument firstly mentions, in the premise, the less effectiveness of trees at absorbing and storing Carbon Dioxide than that of native grasses and then jumps directly over the conclusion saying that these incentives are helping to hasten global warming. This means that the incentives are exacerbating the present situation and which can only happen, as per the argument, if the incentives are actually affecting the current role of native grasses, so that the resultant is more global warming than before.

D states the assumption that is consistent with our thoughts, above.

Aviral1995 · Answer

VeritasKarishma   GMATNinja , could you please explain how to eliminate B?
Is it wrong because - (B) most farmers do not plant any trees on their land unless there is an incentive to do so
we do not know if they are removing grass to plant trees. The land on which they are planting trees may be empty as well.
Please let me know if my reasoning is wrong?

Hanzel101 · Answer

Hi Aviral1995 , I'll just mention my understanding here

Experts, please correct me if I'm wrong. In assumption questions, assumption is the hidden premise, which must be true in order for the conclusion to hold true. Basically, if we reverse that assumption and our conclusion is broken, then that statement is in fact our assumption. Now in B, if we reverse (or negate, as most people say) statement B - most farmers do not plant any trees on their land unless when there is an incentive to do so. Now, does this statement break the conclusion? No. Even if the statement is true, the conclusion will still hold. Hence, B is out. Thanks

KarishmaB · Answer

Many farmers are planting trees because of incentives. 
Trees absorb and store carbon dioxide less effectively than native grasses

Conclusion: These incentives are helping to hasten global warming.

There are incentives to plant trees. Trees are less effective than native grasses. But the conclusion says that these incentives are hastening global warming. So planting of trees is hastening global warming. This would happen only if farmers were removing native grasses to plant trees sometimes. If they are planting trees on barren land, then certainly the incentives are NOT hastening global warming. 
Hence, (D) is certainly an assumption.

As for (B), it is not an assumption. You need the assumption to hold for the conclusion to hold. It doesn't matter to us even if option (B) does not hold. Say farmers do plant some trees anyway. Now more farmers are planting more trees because of incentives. Still the argument stays as it is. If the farmers are replacing grass by trees, then the incentives are hastening global warming. If the farmers are not replacing grass by trees, then the incentives are not hastening global warming.

Doer01 · Answer

Hi Folks,
 Author has presented two types vegetation that absorb/trap carbondioxide: trees and native grass. Farmers get incentive to plant trees.
Grass traps carbon dioxide more effectively than trees.
Conclusion: Planting trees is speeding up global warming.
 How? 
Correct choice must explain how planting trees will speed up global warming even though they trap CO2.

(A) trees not only absorb carbon dioxide but also emit it : ok but how much? Contender, Keep it for now.
(B) most farmers do not plant any trees on their land unless there is an incentive to do so : Even if few are planting, it will slow down global warming to speed it up. Incorrect
(C) land that has been deforested seldom later sustains native grasses : So? This is irrelevant to the discussion here. Incorrect.
(D) some of the trees planted in response to the incentives are planted where native grasses would otherwise be growing : Now, this is something that explains why planting trees could speed up global warming. Say grass was absorbing 100% CO2 but trees are absorbing 70%, means rest of the 30 % is adding more CO2 to the environment, speeding up the process.
(E) few if any governments have been interested in promoting the growth of native grasses : Typical govt. :being interested alone is not going to help. Incorrect.

Source: LSAT

lakshya14 · Answer

"Some" in (D) cannot hasten the global warming since trees are not planted on a large basis according to this statement?

ra96 · Answer

I wanted to choose D but I didn't because of "some". If the argument says this will hasten global warming then wouldn't it make sense that there would need to be "most" of the trees planted .... With "some" you can't really say it will hasten global warming.

In several countries, to slow global warming, many farmers are

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In several countries, to slow global warming, many farmers are

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