The phrase "already changed the world" is correct and usable in written English.
You can use it to indicate that something has had a significant impact or influence on the world at an earlier point in time.
Example: "The invention of the internet has already changed the world in ways we are still discovering."
Alternatives: "has transformed the world" or "has impacted the world."
The Beatles sang derisively about revolution, but by that time they had already changed the world.
Look at how much Korea's successes have already changed the world.
Aware of how much they have already changed the world through their businesses, computer tycoons can turn into impatient broader reformers.
Even without approval by the United States and Russia -- first and fourth on lists of the world's largest emitters of heat-trapping "greenhouse" gases -- the treaty has already changed the world in small but significant ways that will be hard to reverse, these experts say.
In a sunwashed ceremony on Lehman Lawn, the 558 graduates in pale blue recalled how they had already changed the world within the Barnard gates, with a recycling program, a move to socially responsible investing, and, Melissa Marrus, the senior class president, said, the most progressive condom distribution policy in the nation.
Pause for a moment to consider Asia's boom over the last 50 years – the rise of first Japan, then South Korea, now China and maybe next India – and the degree to which it's already changed the world and will continue to change it.
However, this much is clear: the Chinese middle class has already changed the dynamics of the world we live in.
"But the very fact that he was arrested and that his claim of immunity was rejected has already changed the calculus of dictators around the world.
"Recent work is not feminist, like Martha Rosler's or Joan Jonas's, because these women changed the world already.
September 11 changed the world, but only as much as you already wanted it to be changed.
President Trump has been in office just under two months, and a lot has already changed in the world of health care.
