For the first time since the Great Recession ended in 2009, every one of the world's 45 largest economies is growing.

"We haven't seen it for a decade," Jeffrey Kleintop, chief international investment strategist at Charles Schwab, told advisors attending the firm's Schwab Impact conference in Chicago Tuesday. Of course, the last time this happened was in 2006 and 2007.

Is the global economy too good to last? Kleintop doesn't think so, at least not for the next 12 months.

In every part of the world, stocks are "locked into global growth," he noted. In other words, rising earnings are supporting the surge in stock prices.

Even in South Korea, which sits at ground zero for a potential nuclear confrontation with North Korea, the economy is booming.

How do we know it's not a bubble? Kleintop said he examined four bubbles in the last five decades—the Nasdaq tech, home builders, oil and silver bubbles—and discovered a startling similar pattern.

All four of these bubbles inflated at a rate of 1,000 percent over 10 years almost to the precise month before bursting. If one wants to look for a record-setting bubble, Bitcoin is up 1,000 percent in the last year.

Yet it's "hard to say that Bitcoin will tip us into a recession," he said. It's true that FANG stocks are up 1,800 percent since 2009, but they represent only 6 percent of the market. In contrast, the Nasdaq tech bubble was 40 percent of the total market in 2000.

Bears have been bruised and battered. Liz Ann Sonders, Schwab's chief investment strategist, told advisors that at some point they'd come out of hibernation. "We may be entering the late phases" of this bull market, she said.

The U.S. economy is kicking into high gear, with capital expenditures accelerating. This means productivity, a lagging indicator, should pick up, she said.

In contrast to the last expansion, which ended so dismally, household balance sheets are in much better shape. Household income is five times debt-service costs.

In these circumstances, Sonders explained that most American households would be net beneficiaries of rising interest rates.

Another difference she pointed out was that correlations across asset classes and even within the U.S. stock market itself are crashing. In 2008, every financial asset moved in lockstep.

Today, one can find huge divergences with in industries, from technology to industrials. Just look at Honeywell vs. GE.

Valuation metrics are all over the place. Sonders observed that equity risk premium measures such as the ones the Fed uses say valuations are reasonable, but the Shiller CAPE ratio and Warren Buffett's total stock market value-to-GDP ratio point to a "wildly overvalued" equity market.

Her favorite sentiment indicator, the Ned Davis Crowd Sentiment measure, is well into the extreme optimism zone. When it has reached that level, returns over the next 12 months were negative.

Politics are not swaying markets nearly as much as people think, Sonders said. "I don't know any economist who has ratcheted up GDP forecasts" because of tax reform.

Still, there is a possibility that stocks will keep surging higher over the next 12 months the way they have since mid-2016. If this turns into a frothy melt-up, it would hardly be the first. And experience shows they don't end well.