OECD: Iran war erases global growth upgrade, fans inflation

The escalating conflict in the Middle East has knocked the global economy off a stronger growth path, the OECD warned on Thursday, as a near-halt in energy shipments through the Strait of Hormuz threatens to push inflation sharply higher.

The Paris-based Organisation for Economic Cooperation and Development said the global economy had been on course for stronger-than-expected growth before the war in Iran erupted, but that prospect has now all but disappeared.

Global GDP growth is now projected to ease from 3.3% last year to 2.9% in 2026 before edging up to 3.0% in 2027, as an energy price surge and the unpredictable nature of the conflict offset tailwinds from strong technology-related investment, lower effective tariff rates and momentum carried over from 2025.

The projections in its interim Economic Outlook are conditional on a technical assumption that energy market disruption moderates over time, with oil, gas and fertiliser prices declining gradually from mid-2026 onwards.

The 2026 projection is unchanged from the OECD's December forecast, but preliminary indications since then had suggested global GDP growth could have been upwardly revised by around 0.3 percentage points in 2026 had the conflict not escalated — a revision that has been entirely erased by the impact of the fighting.

With energy prices now soaring, G20 inflation is projected to be 1.2 percentage points higher than previously expected in 2026 at 4.0%, before easing to 2.7% in 2027.

US outlook

The war compounds an already complex picture on trade.

US bilateral tariff rates have declined following the US Supreme Court ruling against tariffs imposed under the International Emergency Economic Powers Act, with particularly large reductions for several emerging market economies including Brazil, China and India. Nonetheless, the overall US effective tariff rate remains well above that prevailing prior to 2025.

On individual economies, annual GDP growth in the United States is projected to moderate from 2.0% in 2026 to 1.7% in 2027, as strong AI-related investment is gradually offset by a slowdown in real income growth and consumer spending. The OECD had pencilled in a forecast of 1.7% this year and 1.9% for 2027 in December, before the Supreme Court ruling.

US headline inflation is now forecast to hit 4.2% in 2026, up 1.2 percentage points from the previous projection.

Diverging paths

In China, growth is projected to ease to 4.4% in 2026 and 4.3% in 2027, both in line with the OECD's previous forecasts.

Euro area GDP growth is anticipated to slip to 0.8% in 2026, as higher energy prices weigh on activity, before increasing to 1.2% in 2027 helped by stronger defence spending. That marked a sizeable downgrade from December when the OECD had forecast 1.2% growth in 2026 and 1.4% in 2027.

In Japan, growth is projected at 0.9% in both 2026 and 2027 - both unchanged, as the rising cost of energy imports offsets robust business investment.

The OECD urged central banks to remain vigilant and called on governments to ensure any support measures for households were well-targeted and time-limited.