Well, the Norse in Greenland was the result of a convergence of several factors. It was in studying that that i first became aware of the little ice age and the little climactiv optimum. The Norse had hunted the southeast coast of Greenland ever since they became a truly sea-going people (late 7th/early 8th centuries), but there was no habitable coast there (the Dorset culture "eskimos" had once lived there, but probably more than a 1000 years before the Norse showed up). Various sea-going people, principally pirates and mostly Norse with slaves captured in raids on Ireland and Scotland began settling Iceland in the late 9th century, which was a period of great activity among the northern tribes. This was the same period during which the Danes began the attempt to conquer England.
Most of the new settlers had good reason to leave their homelands, and it wasn't just overcrowding and poor soil. Iceland is hardly a garden island. Usually their former haunts had become too hot for them. A great many of the early settlers were pirates or murderers. Among the Norse, the records (principally sagas transmitted orally and only written down beginning in the 11th century--those copies are gone, and only recensions remain) refer to manslaughter, which reflects the inability to enforce a verdict of murder. Such men would be outlawed, and unless they had very powerful friends, they'd have to get out of Dodge.
Thorvald Asvaldsson was outlawed for manslaughter in Norway, and he left for Iceland with his wife and children, including his adolescent sone Erik--Erik Thorvaldsson, known to history as Erik the Red. Erik himself was accusedd of manslaughter in 980, and was outlawed for three years in 981. He went off to Greenland. Although the Norse could easily cross the Denmark strait to southeast Greenland, and frequently did to hunt pelagic mammals, they found it no more hospitable than their ancestors had done.
But Erik spent three years there, and immediately made for the southwest coast. He then sailed north along that coast, where the most habitable regions lay. He also probably crossed the Davis Strait to Baffin Island, although the sagas are not a reliable source. Skalds may well have known the importance of descriptions of sailing and sailing directions, but the monks who wrote down the sagas, and constantly copied and corrupted them didn't--so there's a good deal of dispute about where exactly he went. However, an account from the Floamanna Saga suggests that at least one Norseman had spent many years somewhere on the North American coast, so Erik's decision to immediately sail to Cape Farewell and around to the southwest coast may have been because he had earlier reports of the region.
When he returned to Iceland in 984, he must have come to some sort of settlement with his enemies (and he brought back an extremely valuable cargo of furs, pelts and "ivory" from pelagic mammals), because he was unmolested as he traveled around Iceland and rounded up settlers. In the early summer of 985, he lead about 30 ships to the new land, of which about 15 or 16 made it. One was Herjolf Bardsson, who was a retired merchant. He took land in the first fjord north of Cape Farewell. His son, Bjarni Herjolfsson, had sailed to Norway the previous year to trade, and when he retuned to Iceland and found his father gone, he sailed for Greenland (i won't go into details, but obviously his father left him detailed information, including the lattitude of Cape Farewell).
Bjarni was driven off course by a storm, and when he could finally once more control his course, he sailed for days and days north along an unkn0wn coastline. It is now evident that he coasted the east coast of Newfoundland and then Labrador. When he reached Cape Chidley at the northern point of Labrador, he turned hard to starboard and sailed for five days, sailing directly into Herjolfsness, his fathers settlement. He almost certainly had gotten detailed information before he left Iceland.
Ten or twelve years later, he sold his ship to Leif Eriksson, and it seems likely the he gave Leif detailed (and exclusive) information about his voyage, including the lattitudes of the land he had sighted. Leif seems to have set out sailing directly south to what would become known as Vinland the Good. The forests of Labrador are coniferous, and the forests of northern Newfoundland are also largely coniferous. But the forests of central and southern Newfoundland are hardwoods, and extremely valuable cargo to sell in Greenland and Iceland. Leif brought back such a cargo and it made him a wealty and influential man.
Certainly the little climactic optimum made the settlement of Greenlandn possible. But other Norse had been there before Erik Thorvaladsson, and they hadn't stayed. The Irish may have been there before the Norse, too--Erik found an abandoned house there on his first voyage, and the Norse routinely referred to Greenland in those days as Irland Mikkla--Greater Ireland. But Greenland was settled due to the strenght of Erik's personality, and his ambition. In Iceland, he was a little man, with no great lands and many powerful enemies. In Greenland, he was a Jarl, a great cheiftan, who dispensed land and honor to his followers. Climate played a part, but it took Erik the Red to make the settlement of Greenland possible.
My history advisor in university once told me (rather pompously) that history is the study of everything. Rather too ambitious, but understanding things like climate is importanat. But it's not as though climate inevitably drew the Norse to Greenland--Erik the Red did that.