What would happen if the Earth's axis didn't tilt?

If the Earth's axis did not tilt, we would not experience the different seasons we have today. The axial tilt is what causes the extremes of seasons, with one hemisphere receiving more direct sunlight than the other. During Summer and Winter, one hemisphere faces towards the Sun while the other turns away. If there was no tilt on the Earth's axis, it would mean that the entire planet would have one season, which is either Spring or Autumn. However, the Earth's elliptical orbit around the Sun would still cause some variation. Earth would still experience a mini Summer during January when it is closest to the Sun and a mini Winter in July when it is farthest from the Sun. But this effect would be a lot smaller compared to the current season variations due to the Earth's axial tilt.