Secretary General of the Association of Spanish Language Academies: Spanish will be the language with the most speakers as a mother tongue by 2050

From an article here in Spanish. Rough translation:

More than a hundred people have gathered for the 45th International Congress of the European Association of Spanish Teachers, where the future of the language was discussed. Secretary General Humberto López Morales gave the inaugural lecture at the conference where he talked about expectations for the coming decades.

"Spanish has a magnificent future, given that there are various studies that show that in 2050 Spanish will be the language with the largest number of speakers as a mother tongue in the world", he said. "In the United States there are 2.5 new Hispanics every minute, which works out to 13 million people per year. In this way this country will become the second-largest country in the world with people that have Spanish as their mother tongue."

(Note: either he's off by a decimal point or the article is, because one would need 25 a minute to work out to 13 million. Considering that the US currently has about 40 million Spanish speakers one would assume that 1.3 million per year makes more sense)

Humberto López also spoke about the need to have an international Spanish dictionary, given the differences in vocabulary from country to country.

Since the subject is population and population growth and the current language with the most speakers as a mother tongue in Chinese, a comparison of several Spanish-speaking countries with China is in order. Here are their population growth rates:



Assuming for the moment that population growth rates stay the same over 40 years (which they won't), that would work out to:

China: 0.5% population growth rate, 22.6% population increase by 2050 (300 million more)

Spanish countries with a growth rate of about 1.2% and a rough estimate of 400 million speakers as a mother tongue: 61% population increase by 2050 (244 million more)

So I'm not sure how Spanish is supposed to have more speakers than Chinese by then.