Based on GDP forecasts, and because it's as a share of GDP, we have to know what the nominal GDP will look like. Meeting the 2% target in 2032-2033 would mean going from the current estimated $41 billion in defence spending to about $82 billion in 2032-2033. That's it. It would be almost doubling expenditures.
On December 3rd, 2024. See this statement in context.