What causes the seasonal changes in temperature on earth? a. because of earth's elliptical orbit, the earth is closer to the sun during summer and farther from the sun during winter. therefore, the hottest months are during the summer, when earth is closest to the sun. b. the sun shines more brightly and emits more energy during the summer, and shines less brightly during the winter. c. the tilt of earth's axis as earth orbits the sun causes longer days and more direct sunlight during summer, and shorter days and less direct sunlight in winter. d. the buildup of greenhouse gases during the summer traps more heat in earth's atmosphere, causing higher temperatures at earth's surface. in the winter, a thinner atmosphere leads to greater heat loss from earth's atmosphere and lower temperatures.