First South Americans Were Australian Aborigines (1999) (opens in new tab)

The Nature article states "some Amazonian Native Americans descend partly from a Native American founding population that carried ancestry more closely related to indigenous Australians, New Guineans and Andaman Islanders than to any present-day Eurasians or Native Americans. This signature is not present to the same extent, or at all, in present-day Northern and Central Americans or in a ~12,600-year-old Clovis-associated genome, suggesting a more diverse set of founding populations of the Americas than previously accepted." That's basically saying "mainstream academia has been wrong to date on an issue as basic as how and when people reached the Americas". There was, however, prior evidence:

Research by Ludwik and Hanka Herschfeld during World War I found that the frequencies of blood groups A,B and O differed greatly from region to region. The "O" blood type (usually resulting from the absence of both A and B alleles) is very common around the world, with a rate of 63% in all human populations. Type "O" is the primary blood type among the indigenous populations of the Americas, in-particular within Central and South America populations, with a frequency of nearly 100%. In indigenous North American populations the frequency of type "A" ranges from 16% to 82%. This suggests again that the initial Amerindians evolved from an isolated population with a minimal number of individuals.

I have been studying traditional navigation techniques of the pacific ocean over the last year or so and visiting museums across the world with surviving traditional and reconstructed craft. After learning the amazing variety of techniques used for navigation (celestial and otherwise) and the innovative food preservation and water collection techniques in recorded use for long sea voyages, I really don't doubt the ability of people to have crossed the Pacific in early craft.

We know that there has been some contact between the Americas and Polynesia, for example, the staple food of the Maori of New Zealand was the kumara, a sweet potato, which are native to the Americas.

His main objection was based, I believe, on predominating currents and winds. However, in an El Nino year, the currents shift and winds shift, and there is evidence that Polynesian migrations eastward coincided with El Nino events.