The death rate decreased after the 1950s because 1. medical care
2. the climate
3. political situations
improved in several nations.
1. wars
2. infant mortality
3. food production
also began dropping dramatically.

1

Explanation:

All the other answers would raise the death rate, except for 3, but that wouldn't have such a profound impact to where the death rate would decrease by a substantial amount

no sé si entiendes español pero te daría la respuesta si lo supiera, pero lo siento mucho

it is very hard for the climatologists to precisely predict how will the global temperatures be changing so there's lots of models, some of which differ significantly, this is due to multiple factors, and probably the most important is the human activity.

humans have been a key factor in climate change around the globe since the start of the industrial revolution, and in the past few decades the consequences are becoming more obvious. there's lots of emission of pollutants in the atmosphere as well as changing the environment on the surface itself, so it's really hard to predict how will that go in the future because there's some countries that are reducing the damage and are going towards green energy, while others are stubbornly continuing with pollution and damages to the environment.