Yellow G-Class stars, like our sun, get warmer as they age... This is nothing surprising.
Keep in mind that the Earth's mean temperature has remained relatively constant over geologic time even though the sun has increased the amount of energy it releases in our general direction by over 25% since the advent of living systems on Earth.
Life, the aggregation of the physical and chemical processes directly associated with the business of living on planet Earth, specifically, is chiefly responsible for maintaining a habitable global mean temperature in the face of solar-based perturbation (as
well as many others that come from Earth itself on a regular, ceaseless basis).
When external perturbation exceeds the homeostatic capabilities of our planet's biological regulatory systems, when negative feedback loops become amplification systems (adding fuel to the fire instead of water...), the Earth will begin a steady march to becoming
a planet like Venus...
Yes. The sun gets hotter as it ages. This fact should always be a part of any model that attempts to predict planetary climate variation and evolution. Fact is, we are building a very reliable gas shield that will trap heat on the surface which will amplify
the warming of Earth's surface to the extent that we may very well all die . The sun will only add fuel to the fire.
Things look pretty grim, theoretically. Don't fool yourselves. Global Warming is real and you can't blame it on the sun. If we do not act immediately and on an unprecidented global scale, then we are doomed.