When CO₂ is released into the atmosphere, it behaves as a greenhouse gas, keeping heat inside the atmosphere. Which of the following is not a consequence of a warmer atmosphere?
The key here is we’re looking for things that are not likely to occur should the atmosphere get warmer. A warmer atmosphere possesses more energy. If you make the simple approximation that the atmosphere is a big ball of gas, it makes sense that more energy leads to more turbulence. Therefore, a warmer atmosphere is more likely to produce more intense storms. Therefore, “More intense storms” is not a correct answer.
What about “Polar ice caps melting at an increased rate”? Well, a higher average temperature of the atmosphere would mean that the polar ice caps are exposed to a higher heat. Therefore, they are more likely to melt quickly. Therefore, this is also not a correct answer.
What about “More atmospheric water vapour, another greenhouse gas”? Well, it is true that water vapour is a greenhouse gas. It’s talked about less as a greenhouse gas because humanity has less power to control their water vapour in the atmosphere. A warmer atmosphere makes more water evaporate.
The truth is that, for each one-degree C rise in global temperatures due to the release of carbon dioxide, there is a further one-degree C rise caused by the water vapour evaporated into the atmosphere because of the extra heat. So we know that a warmer atmosphere would increase the amount of atmospheric water vapour. Therefore, this is another incorrect answer.
What about “More frequent heatwaves”? The introduction of more heat into the atmosphere generates more chaos and more infrequent but extreme weather conditions. Therefore, for a warmer atmosphere, you would expect more frequent heatwaves. This is therefore not a correct answer.
What about “Air too thin to breathe”? Well, we know that since the atmosphere is mostly a gas that its pressure is proportional to its temperature, therefore, we would expect the pressure to rise when the temperature of the atmosphere increases. We also know that the volume of a gas is proportional to its temperature and that the pressure of a gas is inversely proportional to its volume.
It might seem like all these factors are in competition. But actually, they’re in balance. A rise in temperature will increase the local pressure. The volume of the atmosphere as a whole will expand. And the pressure will drop. The final consequence of this is that an increase in the temperature of the atmosphere is unlikely to change the pressure very much. And it would take considerably more heat than we’re discussing here just from global warming in order to make the atmosphere too thin for us to breathe.
Therefore, of the five options given, air too thin to breathe is not a consequence of a warmer atmosphere.