Answer :
The Earth has definitely gone through periods of natural warming and cooling. However, it is absolutely absurd to claim that humans are not making this natural cycle far, far worse by the added emissions and atmospheric destruction.
points for his argument:
regardless of humans, global warming still happens due to the change in atmosphere
natural disasters such as volcanoes also contribute to global warming
against:
humans make global warming worse due to contribution to greenhouse gases e.g. coal mines, burning of fossil fuels, deforestation etc.
the earth gets warmer as these activities increase, showing the correlation.