Nikil Saval writes that “Globalisation could take place in services, capital and ideas … but what it meant most often was making it cheaper to trade across borders” (The great globalisation backlash, 15 July). We hear no more from him about cross-border movements of capital. When I studied economics in the 1950s we spoke of “capital flight” as a major cause of economic stagnation and regulatory capture. The rich in most of South America appeared to be free to invest their winnings in US equities to the detriment of their local industries. My pension fund invests more abroad than in UK equities. Am I complicit in a modern version of capital flight? Could it be that another tenet of conventional wisdom needs to be challenged: that free movement of capital across borders benefits us all?

David Chambers

Stroud, Gloucestershire

• The main drivers of environmental destruction (Earth faces sixth mass extinction, 11 July) are over-population and economic growth. Over-population is caused by poverty. Economic growth – seen by most as a good thing – is needed only to service debt. This was pointed by CH Douglas’s Social Credit movement in the 1920s and more recently by EF Schumacher and others. Allowing banks to issue 97% of money as debt is at the heart of the problem.

Chris Hughes

Leicester

• Join the debate – email guardian.letters@theguardian.com

• Read more Guardian letters – click here to visit gu.com/letters