AP Images

Central banks in some of the world's largest economies are gearing up to deploy new monetary stimulus to stave off a brewing global recession.

But that stimulus might not be enough to prevent a downturn, according to Morgan Stanley.

China, Germany, and the US have also floated various fiscal stimulus measures, including a payroll tax cut, deficit spending, and interest rate cuts.

Morgan Stanley says those fiscal policies may also eventually disappoint.

Visit the Markets Insider homepage for more stories.

A wave of monetary stimulus is expected to hit the global economy in the coming months, but it might not be enough to prevent a recession.

According to Morgan Stanley's chief economist, a combination of low interest rates, rising debt levels, and trade-policy uncertainty has created an environment where monetary policy won't be as effective as it used to be.

"Declining natural interest rates have meant that monetary policy by itself will not be enough to stimulate aggregate demand and lift inflation expectations," Chetan Ahya, Morgan Stanley's Chief Economist said in a note to clients on Sunday.

He continued: "Cyclical developments have made matters worse. Trade policy uncertainty is pushing global growth to a post-crisis low."

Markets Insider is looking for a panel of millennial investors. If you're active in the markets, CLICK HERE to sign up.

The commentary comes as fears of a global recession have begun to boil over amid alarming economic data from such large economies as Germany and China.

The US has also seen a closely watched segment of the so-called yield curve - which tracks the spreads between short- and long-dated Treasury bonds - invert for the first time since 2007. The most recent inversion added to existing concerns of an economic slowdown as the occurrence has preceded every recession since 1950.

"Lingering trade-related uncertainty has put the wheels of a global slowdown in motion," Ahya said.

This confluence of factors leaves fiscal policy measures as the preferred avenue for avoiding a recession.

Germany, China, and the US have all suggested different fiscal methods outside of monetary easing in order to shore up their economies in the face of a looming recession. But Morgan Stanley remains unimpressed. In the end, the firm thinks the situation may be too far gone for some overarching solution.

"Political and legal constraints leavel ittle room for aggressive fiscal action in the near term," the Morgan Stanley analysts said. "While some fiscal stimulus is under way this year, we expect limited further expansion next year."

For your reference, here are the fiscal measures recently floated by each country, with accompanying commentary from Morgan Stanley. Spoiler alert: it's probably not best to get your hopes up.