It seems Dr. Michio Kaku is a Theoretical Physicist. He has given a very interesting explanation on Type 0/1/2/3 Civilizations in this YouTube Video. Do see it. I have given a small teaser below from that video which will enable you to guess the direction of the discussion.
“When we physicists look in outer space for alien life, we don’t look for little green men. We look for Type-1/Type-2/Type-3 civilizations.
A Type-1 civilization has harnessed its planetary power. They control earthquakes, the weather, volcanoes, they have cities on the ocean, anything planetary – they control. That’s Type-1 civilization.
A Type-2 civilization is stellar. They have exhausted the power of the planet, and they get their energy directly from their mother star. They use the power of the sun itself to energize their huge machines.
Eventually they exhaust the power of a star and go galactic. They harness the power of billions of stars within a galaxy (Thats a Type-3 civilization).
Now what are we on this scale? We are Type-0. We don’t even rate on this scale. We get our energy from not stars and galaxies, but from dead plants – Oil and coal. But we can calculate when we will attain Type-1 status – In about a hundred years!
We are seeing the beginnings of a Type-1 economy. Huge planetary trading blocks are the beginnings of a planetary economy (Referring to European Union, NAFTA, etc). And what is the Internet? The Internet is the beginning of a Type-1 telephone/communications system.
The mathematics says that there should be thousands of Type-1, 2 and 3 civilizations in the galaxy. But we see no evidence of it anywhere. And why is that? Because, the transition from Type-0 to Type-1 is the most dangerous of all transitions. We may not make it. Its a race against time.
On one hand, we have the forces of Integration – the forces of tolerance and multi-cultural fabric emerging before our eyes, on the other hand, we have weapons of mass destruction, germ warfare, nuclear warfare, rise of international terrorism – They are obstacles to reaching a Type-1 civilization”