I was reading an essay about the environment and how we can save the forests. But actually while reading I felt that the following sentence is not correct, it used the plural are instead of is as I think it should. Look the sentence:

...Is this a problem? Yes it certainly is.
First, rising CO2 levels are causing global warming.

I think the (rising) in CO2 levels is the cause of the global warming, then the sentence must use the singular is. Why did it use the plural? How can you explain this?

Sorry if the question is too basic.

  • 2
    Rising is a Participle and you should actually consider the plural noun "Levels" which is referring to co2 emitters around the world.
    – user3214
    Commented Jun 8, 2014 at 15:54
  • The sentence would use the singular is if it was phrased like so: First, the rising of CO2 levels is causing global warming.
    – Pockets
    Commented Jun 8, 2014 at 17:51
  • 2
    Contrast rising with raising.
    – user230
    Commented Jun 8, 2014 at 23:10
  • I don't know why you want to contrast rising with raising...Actually,this essay is taken from a curriculum i've studied before and it was written(rising).Why do you want to contrast?
    – kathrine
    Commented Jun 9, 2014 at 9:56
  • rising is an adjective here. @snailplane Am I missing something with your word contrast?
    – Maulik V
    Commented Jun 9, 2014 at 11:16

3 Answers 3


You can say:

"The rising in CO2 levels is causing..."

"The rising CO2 levels are causing..."

"The rising CO2 level is causing..."

All of these are correct grammatically but are slightly different in what is being stated.

In the first "the rising" (a noun) is the singular subject. In the second "CO2 levels" is the plural subject (rising is an adjective). In the third "CO2 level" is the singular subject (rising is an adjective).

There is really only one global CO2 level since atmospheric mixing is quick and efficient on the scale of the release process, so a singular is technically correct (but "levels" is okay also).


The rising CO2 levels are causing

The subject in this sentence is CO2 levels.

rising describes the subject, like an adjective would.

Rising CO2 levels are causing

The jumping little children are hyper.

The falling trees are dangerous

Susie's singing, dancing, green frog is dying.


I would propose that one uses the plural when what one is observing can not be properly observed at just one location. The use of the singular might be taken as implying a local anomaly.

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