U.S. President George W. Bush upset some delegates by failing to mention "climate change" or "global warming" in his final speech to the United Nations -- in which he referred to terrorism 32 times.

Exactly a year ago, the United Nations held a special summit about climate change -- U.N. Secretary General Ban Ki-moon calls fighting global warming his "signature issue" and many governments see it as the biggest long-term challenge.

Bush clearly has a lot to worry about such as the global financial crisis, wars in Iraq and Afghanistan and how to prevent the spread of nuclear weapons. Yet while he spoke a lot about terrorism in his speech on Tuesday, he did also refer to other problems such as human rights in Burma, violence in Darfur, the Doha trade round and the fight against malaria.

Climate change didn't get a mention, even though Bush has called it a "serious problem" and signed up at the Group of Eight nations in Japan in July to a vision of halving world greenhouse gas emissions by 2050. China and the United States are the main emitters of greenhouse gases, mainly from burning fossil fuels.

"It was a surprise and a shame that President Bush didn't once mention climate change," the Norwegian daily Aftenposten quoted Prime Minister Jens Stoltenberg as saying, adding that he was pleased that both candidates to succeed Bush in January -- Barack Obama and John McCain -- were making it a priority.

So was it just Bush, often accused by many of his closest industrial allies of failing to take climate change seriously enough?

Or perhaps it's impossible to list everything in a speech without making it a dull shopping list of the world's woes?

Or is a speech by a U.S. leader that omits to mention global warming a sign that the world is turning to other issues?

What do you think?

What do you serve world leaders for lunch at a U.N. summit trying to solve a crisis caused by soaring food prices?

You clearly want to impress dozens of heads of state but without laying on opulent meals when up to 1 billion people are threatened by hunger.

U.N. organisers of the June 3-5 food summit in Rome are treading a fine line, putting typically Italian ingredients on the menus, such as mozzarella cheese, pasta, spinach, beans, risotto and parmesan. No pizzas, though.

The main exception to traditional Italian ingredients are pineapples, requiring more energy to transport from the tropics. Veal is on the menu twice and beef once -- environmentalists say vegetarianism is best for the climate because cows need to eat about 16 kilos of grain or grass to put on a kilo of meat.

So here is Tuesday's menu:

Vol au vent with maize and mozzarella

Pasta with a cream of pumpkin and prawns

Braised veal slices with cherry tomatoes and basil

Spinach a la romaine

Fruit salad with ice cream

 They have even gone easy on the wine: today it is the Orvieto Classico Poggio Calvelli 2005; not among Italy's most expensive.

Any better advice? Maybe they should all go vegetarian?