I don't buy that time line. How on Earth could they possibly know all that time ago? It's pure theorising, some egg head's opinion. Meteorological equipment or tech is about 200 years give or take. Before that what did they use? Yes we have historians, authors and famous diaries. The level of fine measurements and accurate readings just were not invented yet. I refuse to feel guilty over what is essentially speculation.
Anyway my opinion is probably wrong, might be right. What are we doing to combat pollution should be the question. CO2 is not the enemy. It is over shadowing legit pollution problems. Cycle to work, don't drive. Eat Vegan and cut sugar out of your diet. Recycle like a nutter. If you are not doing these things then please start. You'll feel great, the air will be fresher and it will cost you very little at the dentist. Oh and your concentration will go up and off the charts.
A plant based diet is a first step towards a cleaner environment. Forget about CO2. SO2 and CO should be the real concern.
But then we'd be eating all the food that food eats. Think of the poor animals. They'll starve.