Thank heaven earnings season kicks off with Alcoa (AA). That's the first time I have said that in four years, and it's pretty monumental when you think about it.

I have always held that Alcoa's outlook is perhaps the most important one offered by any company, and in this case it's for accelerating worldwide growth -- specifically, 7% going to 8%. It also issued a global aluminum forecast of 7%, a nice pick-up from the 6% I expected, which was last year's number.

How is that possible in a world where growth is not so hot in the U.S., while Europe is actually dropping again? The answer, simply, is China. A gigantic acceleration is going on in that country, according to CEO Klaus Kleinfeld, with potential now for a return to double-digit growth of 11%. That's up significantly from the high-single-digit growth we've been seeing, and from what most had been expecting. This is coming from solid demand in aerospace, in infrastructure, in trucks and in autos, specifically in sport-utility vehicles.

This is tremendous news for those of you trying to figure out what 2013 looks like, and it falls right in the hands of the Chinese government, which Kleinfeld credits for turning on the jets in the fourth quarter.

But it isn't all China. Russia, Brazil and India have begun to reaccelerate, as well. That, plus steady, albeit slow growth in the U.S., and a slowing in the rate of decline in Europe, is also included in the worldwide acceleration. Put simply, Europe can't drag down the world as fast as China is pulling it up.

Where Alcoa's projections are most encouraging are in the line-by-line items of each product. Also quite positive is the potential for climbs in alumina and aluminum, the base products, because of tightening worldwide inventories.

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Kleinfeld sees U.S. auto production going from 15.5 million to 16 million, almost back almost to pre-recession levels. In China, he expects auto sales to grow at 7% to 10%, up from 6% to 7% last year. That is most encouraging.

Heavy trucks, giant users of aluminum, will be down 15% to 19%. But, again, that's a decline in the rate of decline -- something that's so important to include in any calculation. Last year, it sank 15%. One look at Europe, where production will be down to about 6% to 10%, instead of last year's decline of 12%, tells the story. China is going to see a dramatic re-acceleration in truck growth, perhaps to as much as 12% to 19%.

Put it all together, and you see a world in resurgence, with aluminum part of that resurgence -- tremendous news for worldwide economics.

Of course, this is terrific news for Alcoa, too. It's enjoying great gains in free cash flow, including a decline in energy costs and an increase in productivity -- quite a repudiation of a now-questionable review by Moody's, especially when you see cash building and debt declining.

To me, this is an inflection point -- the long-awaited inflection point for both the commodity and Alcoa itself. It cheered me, and it should cheer you. It's a very strong start to earnings season from a company that has a very good handle on the global economy and all of its attendant segments.

Jim Cramer is a co-founder of TheStreet and contributes daily market commentary to the financial news network's sites. Follow his trades for Action Alerts PLUS, which Cramer co-manages as a charitable trust and has no positions in stocks mentioned.

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