Sentence Correction

Some climatologists, while admitting that the burning of fossil fuels have raised the level of CO2 in the atmosphere and have caused an increase in the level of global temperature, argue that both these effects are contributing to an abundance of plant mass and thereby leading to heightened consumption of CO2 levels, and bringing down the temperature

(A) Some climatologists, while admitting that the burning of fossil fuels have raised the level of CO2 in the atmosphere and have caused an increase in the level of global temperature, argue that both these effects are contributing to an abundance of plant mass and thereby leading to heightened consumption of CO2 levels, and bringing down the temperature

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(B) While admitting that the burning of fossil fuels raise the level of CO2 in the atmosphere and cause an increase in the level of global temperature, some climatologists argue that both these effects are contributing to an abundance of plant mass and thereby leading to heightened consumption of CO2 levels, bringing down the temperature

© While admitting that the burning of fossil fuels has raised the level of CO2 in the atmosphere and has caused an increase in the level of global temperature, some climatologists have argued that both these effects have contributed to an abundance of plant mass and thereby have lead to heightened consumption of CO2 levels, having brought down the temperature

(D) Some climatologists, while admitting that the burning of fossil fuels raises the level of CO2 in the atmosphere and causes an increase in the level of global temperature, argue that both these effects contribute to an abundance of plant mass, thereby leading to heightened consumption of CO2 levels, and bringing down the temperature

(E) Some climatologists, while admitting that the burning of fossil fuels raise the level of CO2 in the atmosphere and cause an increase in the level of global temperature, argue that both these effects are contributing to an abundance of plant mass and thereby leading to heightened consumption of CO2 levels, bringing down the temperature

I am confused with Options A and E? What is the role of thereby/ and thereby? Experts opinion on this please.

OA D