Bankers and financial economists are working with mathematical biologists to learn lessons about resilience from natural ecosystems – from fisheries to forests – and from the spread of disease. The exercise is certainly of more than academic interest. Andrew Haldane, executive director for financial stability at the Bank of England, says the regulatory structure for banking may be shaped by studies now in progress that treat global finance as a “complex adaptive system” like a living ecosystem.
Eu já tinha lido que as cidades se desenvolvem como organismos vivos, algo que já me bolou. Mas a economia também??
Some policy conclusions are already clear. One is that the banking system has become at the same time too complex and too homogeneous. The problem is that over the past 20 years or so almost all the big globally active banks diversified their holdings and risk, moving into increasingly complex (and opaque) financial instruments. Unfortunately for the stability of the whole system, banks all diversified their business lines in a similar way and, in the process, became inextricably interdependent.
“From an individual firm’s perspective, these strategies looked like sensible attempts to purge risk through diversification: more eggs are being placed in the basket,” says Mr Haldane. “Viewed across the system as a whole, however, it is clear now that these strategies generated the opposite result: the greater the number of eggs, the greater the fragility of the basket – and the greater the probability of bad eggs.”
That is what a mathematical ecologist would have predicted if he or she had known what was going on in the world of finance. The tropical rainforest, for example, has so many interdependent species that it is more vulnerable to an external shock than the simpler ecological diversity of savannahs and grasslands.
Mathematical biology also helps to explain in retrospect why hedge funds, the institutions once thought to be at greatest risk of financial collapse, have survived the crisis in a healthy state. Compared with banking, the hedge fund sector is populated with relatively small, specialised players – the robust structure of a diverse ecosystem.
Puta que pariu…
Economists talking about “efficient” or “perfect” markets remind Lord May of ecologists talking about “the balance of nature” 40 years ago, when ecosystems with a rich web of interactions were thought to be the most stable. Subsequent analysis has shown the opposite to be the case: the most robust systems can be decoupled into discrete components without collapsing.