The text points out that the factors affecting global warming are greenhouse gasses and human activity. This is shown by the quote" concentration of greenhouse gasses, especially CO2 have increased substantially since the beginning of the industrial revolution". This is because it said that there was an increase in the number of green house gasses released due to human activity now and in the past, that can be traced back to the the industrial revolution.
The cotton gin helped separate cotton from the seed after picking.... which is why slavery actually increased with its introduction because plantations could process more cotton, but needed people to pick it beforehand.