The manufacturing slowdown in the US and China has arguably been the most disconcerting world economic story of recent months. After all, the US and China are respectively the world’s first and second largest economies.

But new manufacturing surveys offer hope that growth may be coming back.

“A pulse returns to global manufacturing,” JPMorgan’s Bruce Kasman said.

China’s manufacturing PMI unexpectedly jumped to 50.2 in March, signaling expansion for the first time since July. In the US, the ISM manufacturing index jumped to 51.8 in March, signaling expansion for the first time since August. Manufacturing PMIs in Europe also reflected acceleration, albeit modest acceleration.

Optimism tempered with skepticism

The strong dollar, low energy prices, and floundering demand in export markets have been putting pressure on the US manufacturing sector, which has been stagnant for months. Meanwhile in China, policymakers have been proactively shifting the economy to one more reliant on consumption than exports and investment, which has put pressure on the country's domestic manufacturing sector.

Most economists on Wall Street were encouraged by the numbers.

“Global manufacturing confidence improved notably in March, led by US and China,” Barclays’ Apolline Menut said.

“Manufacturers see daylight again,” Bank of Tokyo-Mitsubishi’s Chris Rupkey said.

“This surprisingly strong official [Chinese manufacturing] PMI release points to stronger growth momentum in March and was largely supported by domestic demand, especially property and infrastructure investment as a result of policy easing,” Nomura’s Yang Zhao said.

But some economists struggled to make sense of some of the numbers.

“The problem is that the magnitude of the rebound in US manufacturing sentiment is hard to explain,” Capital Economics’ Steve Murphy said. “True, the dollar has depreciated somewhat recently, but currency movements take much longer to feed into actual activity and some of that past appreciation should still continue feeding through.”

Time will tell

JPMorgan and Markit produce a an aggregate global manufacturing PMI, with the US and China weighted most heavily. The index climbed to 50.5 in March from the stagnant 50.0 level in February.

“The survey level is by no means strong but reverses much of the last two months’ slide,” JPMorgan’s Bruce Kasman said. “The details of the report were also encouraging — notably the rise in the orders/inventory ratio and the large improvement in China’s and other EM Asian countries’ PMIs. This positive message was reinforced by March national surveys moving higher in in Japan, Germany, and the US.”