Anglo-Dutch oil company Royal Dutch Shell pledged an ambitious 4.7% increase in its quarterly dividend on Thursday and pushed ahead with plans to deliver more oil and gas, despite an "uncertain" outlook for some parts of the world economy.

The company was delivering profits that undershot expectations at $5.582 billion for the fourth quarter on an addusted current cost of supply basis, up from $4.846 billion a year ago thanks in part to stronger refining margins, but compared with expectations of around $6.2 billion.

However, analysts have said its strong cashflow outlook for the years ahead justify a higher payout.

The company pledged a net $33 billion of capital spending for next year, some of which will go into controversial places like Nigeria, where a Dutch court this week found its local subsidiary partly responsible for pollution, and into the Arctic, where it suffered a series of accidents last year that have raised new questions about the safety of offshore drilling there.

Shell said it would keep investing despite "headwinds" and despite an "uncertain" economic outlook in some of its markets.

Shell has a strong flow of new projects coming on stream in the coming years to support the higher dividend.

It plans to deliver $175-$200 billion of total cash flow from operations for 2012-2015 and a net capital spending program of $120-$130 billion.

"Shell's efforts to expand its pipeline of potential energy projects are paying off," said Chief Executive Peter Voser. "Our drive to increase our options for future projects means that we are more constrained by limits on capital than by limits on opportunities."

Looking further ahead though, the world number two and its peers are under pressure as the costs of finding and producing new resources rise towards a static oil price, and globally, the oil sector was a relatively poor performer in 2012.