How and why did changes in the environmental conditions affect carrying capacity in this?

Scenario? Recall the scenarios: 0–15 years, harsh winter; 15–30 years, harsh winter and cold spring;

30–45 years, harsh winter, Cold spring, and hot summer.

Climate change does not only refer to global warming. While, yes, it is true that the temperatures during the summer season will become higher, it is also possible that the winter season will be colder still. From year 0 to 15, the winters will be extremely cold as a result of this effect. The rise in temperatures will cause the ice caps and glaciers to continue to melt, resulting in cold springs as well, as shown in the 15 to 30 years scenario. From the 30 to 45 years interval, it seems that the increase in temperature during the summer months have reached higher than what was recorded in the previous years.

Hope that answers the question, have a great day!