How does an increase in ambient temperature affect the density altitude of an aerodrome, and what is its operational effect on departing aircraft?

1. It increases the density altitude, which decreases air density and degrades engine thrust and aerodynamic lift.
2. It decreases the density altitude, which increases air density and improves takeoff climb performance.
3. It increases the density altitude, which increases air density and reduces the runway length required.
4. It decreases the density altitude, which decreases air density and increases engine torque.