The Group of Eight (G8) rich nations will likely agree to an "aspirational" target for cutting greenhouse gas emissions by 2050 but shun mid-term goals at a July summit, the top UN climate official said yesterday.

Ministers and representatives from the G8 and major emerging countries gathered last weekend in Japan to try to build momentum for UN-led climate change talks, but remained at odds over who should do what when, and how much.

"Given the stage that we are in the negotiations, it's going to be quite difficult to get an outcome of the G8 summit that is really strong," Yvo de Boer, head of the UN Climate Change Secretariat, told reporters after talks among environment ministers from the G8 and major emerging countries.