better or worse

when youre saying that something worsens global warming eg. haiki gassu,
do you say that haiki gassu helps global warming, or that it worsens it?
chikyuu no ondanka ha ____

"worsen the global warming" sounds strange for me (but im kinda dizzy right now)

but 地球温暖化が悪化している - "Global warming is getting worse" (this is ,without a doer, the warming will seem to get worse by itself)

or [Insert your cause here] が地球温暖化を悪化させる - " ~~ worsens global warming" (you will have to insert a cause to the warming before the が if you pick this sentence)

obs: 温暖化 itself has the very handy kanji "化" which gives it a "moving/changing" feeling, and will allow you to add する to the word.

You can say 排気ガスが地球温暖化を悪化させている .

You wouldn't say it "helps" global warming, but you wouldn't say this in English either. Or, you could say it, but it sure sounds funny.

One option might be 温暖化を促進する (promoting global warming)

In English you'd probably say "Exhaust gases contribute to global warming."

Another word you'll see quite frequently when "x makes y worse" or "y becomes worse due to x" is the word 加速 (accelerate):

加速する to accelerate
加速させるto cause to accelerate

Considering the OP's current level, answers loaded with kanji aren't going to be terribly useful. It would be a kindness to also include a kana and/or romaji version as well.

UPDATED with hiragana and rōmaji (per Mike Cash san's suggestion...good point)...I also added some example sentences from the web:

Another word you'll see quite frequently when "x makes y worse" or "y becomes worse due to x" is the word 加速 [かそく kasoku] (accelerate):

加速する [かそくする kasoku suru] to accelerate
加速させる[かそくさせる kasoku saseru] to cause to accelerate

Examples:
土壌からでるCO2が温暖化を加速する？
どじょうからでるCO2がおんだんかをかそくする？
dojou kara deru CO2 ga ondanka wo kasoku suru?
Does CO2 emitted from the soil accelerate global warming?

人口増加が地球温暖化と大量絶滅を加速させる
じんこうぞうかがちきゅうおんだんかとたいりょうぜつめつをかそくさせる
jinkouzouka ga chikyuu ondanka to tairyou zetsumetsu wo kasoku saseru
Population growth accelerates global warming and mass extinction

加速する地球温暖化
かそくするちきゅうおんだんか
kasoku suru chikyuu ondanka
Accelerating global warming [Global warming is accelerating]

BTW, CO2 in Japanese is 二酸化炭素 にさんかたんそ nisankatanso