Global warming really isn't just a local problem...universal warming ran through the universe 11 billion years ago, doubling the temperature of intergalactic helium. The cosmic temperature spike was so bad, it stopped galaxies from developing for 500 million years.
Between about 11.7 and 11.3 billion years ago, the universe underwent a massive ionization process, as electrons were ripped from ancient helium atoms. This heated up the atoms in the intergalactic gas from 18,000 to 40,000 degrees Fahreheit. This massive spike prevented them from collapsing into each other to form new stars. Some of the tiniest galaxies even started losing their gas back into the rest of the cosmos. All told, the chaos stunted the development of some of the smaller galaxies by up to half a billion years.
This process was a product of the chaotic nature of the young universe. Galactic collisions were commonplace, growing the size of supermassive black holes to almost unimaginable proportions. The black holes transformed the gravitational energy from these mergers into huge bursts of ultraviolet light, which zoomed out of the galaxies and began the ionization of the intergalactic helium.
To find out more about the effects of universal warming and how modern researchers detected this cosmically ancient temperature spike, check out the original paper over at the Astrophysical Journal and this piece at the Daily Galaxy.