The effects of global warming on the polar ice caps have been studied with computer models. According to some models,...

ryanconnor1234 on June 9, 2020

@avi I'm not an instructor, but I've noticed that they don't answer questions all that frequently (I've seen multiple questions go unanswered for 5 months or more...). I had the exact same question as I was between the two answer choices. I think D is wrong because, although it is possible that the lower freezing point could account for more ice, it's not certain that it would. Say the current state is that the sea temperature is 20 degrees celsius and that the freezing point of the seawater in this state is 0 degrees celsius. In this situation, the freezing point is lower than the sea temperature, so no freezing would occur. Now, say that the changes stated in the passage occur and the sea temperature increases to 25 degrees celsius...if we took answer choice D to be true, meaning that there would be an lowering in the freezing point, that freezing point could only rise to 5 degrees celsius. In this new state, the corresponding rise in both the sea temperature and the sea's freezing point are the same and no new freezing would occur, since the new freezing point is still substantially lower than the sea temperature. This is my understanding of why D is wrong, but I may be incorrect in my reasoning! I hope this helps.

avif on June 9, 2020

Thanks so much! I have been having trouble with the instructors answering questions too. I appreciate your good Samaritan act. What you are saying does make sense.

Kyland on January 7, 2022

If it lowers the temperature needed to freeze water would that not make it harder to freeze water? Temperature goes up while freezing point goes down. It would have the opposite effect. At first it is a little confusing to think about, but that's is how i came to think about that answer choice.

Kyland on January 7, 2022

@avi

Jordan-Schlinger on January 17, 2022

Hey guys I just want to let y'all know they we do have a new team on the message boards, we are here to help!

A is indeed the correct answer. It says that the VOLUME of the ice caps will increase. This does not necessarily mean that it has to expand outwards, it could expand up via frozen rain, and A does that for us.

D looks good, but as you correctly pointed out lowering the freezing point is a negative not a positive. They use all the right words, but say the wrong thing and thus D is wrong.