[Grammar] that our way of life is putting an unprecedented strain on the Earth's ecosystems

[nininaz]

Hello all,

I don't know what 'that' mean in the example below:

The advances made by humans have made us the dominant species on our planet. However, several eminent scientists are concerned that we have become too successful, that our way of life is putting an unprecedented strain on the Earth's ecosystems and threatening our future as a species.

Source:Cambridge Vocabulary


Can we rewrite as the following?( I have doubt )

The advances made by humans have made us the dominant species on our planet. However, several eminent scientists are concerned that we have become too successful, (and scientists are concerned) that our way of life is putting an unprecedented strain on the Earth's ecosystems and threatening our future as a species.

 

[Skrej]

Yes, you are correct. We omit repetition of that clause because it's redundant and unnecessarily wordy.

Imagine if there were several additional things in the list that the scientists were concerned about - it would make for an extremely long sentence if you repeated it for each element in the list.

 

[nininaz]

Yes, you are correct. We omit repetition of that clause because it's redundant and unnecessarily wordy.

Imagine if there were several additional things in the list that the scientists were concerned about - it would make for an extremely long sentence if you repeated it for each element in the list.

Thanks teacher.
The mains reason I have doubt was that the writer didn't connect the sentences with coordinator 'and' and only put ','.
Isn't it wrong connecting two sentences just using ','?

 

[GoesStation]

Some editors might prefer a semicolon there. However, semicolons are used less and less and are increasingly replaced by commas.