Just a Thought
Looking at the two maps below, it hit me. One of the biggest differences between liberals and conservatives is where they live. Liberals tend to live in big cities, conservatives in small towns. So when liberals say man is ruining the planet, this is based on their experience in a big city. When liberals say we need more mass transit and fewer cars, that makes excellent sense in a big city.
This does indicate one reason the Democrats have declined since the 1960s. Many people would rather raise children in the suburbs than in the cities. As people move out of the cities their needs and desires change, as does their outlook.
On the other hand, it doesn't explain everything. For example, why should liberals be soft on crime living in areas where the crime rate is higher?