If the Earth's axis tilted 45 degrees instead of the current 23.5 degrees, the seasons would be far more pronounced than they are, and the poles would be warmer overall. An axial tilt of 45 degrees would bring more heat to bear on the hemisphere facing the sun. But if Earth's axis tilted to 90 degrees, extreme seasons would cause intense climate change on every continent. During the summer, the Northern Hemisphere would experience nearly 24 hours of sunlight for months, which could melt ice caps, raise sea levels, and flood coastal cities.