ęggplant

Our orbit is slightly elliptical, there's a variance of almost 3 million miles ( that's 4.8 million km). I'm certain if our orbit decayed 1.5m km you wouldn't notice much difference. Funny thing is, our aphelion is during Solstice where we endure the hot summer and the frigid winter.

You would absolutely notice the difference. The difference you mentioned is between the closest and farthest distance the earth travels from the sun. At it closest adding the 1.5 million km would place the earth just out of the Goldilock zone. Given the atmospheric changes that would occur much of the globe would be a death sentence for humans. Humans can survive in temperatures up to around 140 degrees (F) if they can sweat to cool down. The humidity would rise drastically due to a major greenhouse effect the would occur. This would mean without outside cooling the human body would cook itself to death.