Oil: Oil at about $80 a barrel is close to being too expensive for the world. Saudi Arabia and the other big producers ought to be thinking about slowing the ascent of the price of crude. But they will probably be happy to watch oil drift higher. Most Gulf states, and Russia, balance their budgets at about $65 a barrel. Saudi leaders have suggested that $75 is the right price – high enough to prevent customers getting restive, but low enough to keep them from thinking too hard about using less or trying alternatives. Abdallah Salem el-Badri, the secretary general of oil cartel Opec, has suggested $80 is needed to keep up investment.

The current price may not yet be above everyone’s target. But the 20 per cent increase in less than a month suggests the time has come for the big producers to rethink their resistance to upping production. It is easy for them to find justifications for yet higher prices. El-Badri pointed out the average price of a barrel of crude so far in 2009 is only $57 – well below Opec’s desired price. Dollar weakness reduces the buying power of $80 oil. And perhaps producers need to pay back big debts.

The difficulty is that even if producers wanted to flood the market, they would have their work cut out. The recent rally has come despite ample inventories. Close co-ordination among producers has generally kept the supply and demand for oil pretty well balanced.

That pattern is sadly familiar. When the oil price sped to well over $100 as the financial crisis was coming, analysts rationalised the rise with theories of an imminent supply squeeze caused by overwhelming demand from fast-growing Asian economies. In reality, a huge supply of ready money – from commodity funds and industrial buyers – ruled the market. Something similar is happening now. If the liquidity keeps flowing, one result is likely to be triple-digit oil. And the big producers won’t worry too much if they are powerless to stop it.

China/Africa: Chinese growing investment in sub-Saharan Africa is both a huge global development and a short-term bubble. Both sides will benefit, but there may need to be some pain first. In 2008, China’s $106.8 billion bilateral trade with sub-Saharan Africa made it the region’s largest trading partner, surpassing the US’s $104.6 billion. The Africa-China trade is close to balanced, while Africa’s exports to the US, mostly raw materials, are worth five times as much as its imports.

China/Africa: Chinese growing investment in sub-Saharan Africa is both a huge global development and a short-term bubble. Both sides will benefit, but there may need to be some pain first. In 2008, China’s $106.8 billion bilateral trade with sub-Saharan Africa made it the region’s largest trading partner, surpassing the US’s $104.6 billion. The Africa-China trade is close to balanced, while Africa’s exports to the US, mostly raw materials, are worth five times as much as its imports.

Like the Americans, the Chinese are mostly interested in key raw materials, especially oil. The China National Offshore Oil Corporation (CNOOC) is in heated rivalry with ExxonMobil over a $4 billion investment in Ghana’s offshore Jubilee field, and is said to be bidding over $20 billion for some 23 Nigerian oil exploration blocks currently controlled by Shell, Total and Chevron. The Chinese government is also in discussions with Kenya about a $3.5 billion port investment to provide an additional outlet for Chinese oil from southern Sudan.

Chinese investment in Africa takes two forms, capital and labour service contracts to employ both Chinese and African workers. In the first half of 2009, China’s cash investment totalled only $552 million, but labour service contracts totalling $22.4 billion were signed, up 25 per cent from the previous year.

While raw materials are still the centre of Chinese attention, the boom at home has provided funds for ventures in other fields, some more sensible then others. China is building a WiMax communications network in Kenya. That may make economic sense, but plans to make Zimbabwe the African centre for solar panel manufacturing must surely be optimistic. From Africa’s point of view, Chinese investment is very welcome; it is a second investment source to the US multinationals, with significantly different characteristics. The two countries’ competition in Africa may well have contributed significantly to that continent’s much better growth record in the 2000s compared with previous decades. Nevertheless, such enthusiasm from so many Chinese investors must be creating some bubbles. Popping will be hard to avoid.