The earth has provided the conditions for life for millions of years. The living and inanimate parts of the earth form a complex interacting system that have kept the global climate stable over long periods of time, punctuated by short periods of change. The long periods of stability created by this self-regulating system have enabled life - and more recently humans - to flourish. However, these stable periods are not always that agreeable for humans - it is after all only 10,000 years ago that the last Ice Age ended - when Malvern, where I am writing this, would have been buried under the southern edge of an ice sheet.
Until relatively recently, we have been very aware of our connection to and dependence on our physical environment. The changing seasons, night and day, rain and drought all directly affected how we lived our lives. But now many of us live in climate-controlled environments which insulate us both from the daily and annual cycles and from moment to moment experience of the rain, wind and sun.
This has had an important psychological consequence. We have started to believe that we are not dependent on the Earth being an agreeable place to live. We act as if we can thrive and prosper whatever happens to the planet. We seem to forget that we are fundamentally dependent on the physical environment to sustain our lives, societies and cultures. The growing power of our technology has enabled us to have an increasing impact on the biosphere. We increasingly pollute our environment and destabilise the climate - but without knowing, or appearing to care, knowing how this will affect the ability of the planet to sustain human life. Perhaps we will be lucky and the planet will process all the CO2, methane etc being emitted without any significant climate destabilisation. Perhaps. But we know the climate has changed dramatically in the past (eg the Ice Ages) through natural causes. And now there is a broad scientific consensus that our activities can change the climate. There are changes already happening with larger ones predicted. We are playing a dangerous game.
But even if we dismiss the impact of degrading our physical environment and the reality of climate change (as some still do), we face another major threat to our existing way of life - we are running out of key resources. Every year we consume 1 million years of 'ancient sunlight', the solar energy stored as oil, coal and gas. This is a finite resource. The term 'Peak Oil' has been coined to refer to the time at which the maximum global petroleum production is reached and from when, if global consumption is not reined in, availability of oil will drop and prices start to rise, perhaps abruptly. Peak Oil in the United States occurred in the late 1960s. Globally, liberal estimates suggest that Peak Oil will occur in the 2020s or 2030s; conservative estimates that we have already passed the point. With the economies of countries like India and China expanding rapidly, oil use seems set to rise massively, even if the West reins in its consumption. Continuing to base our economies on oil is not an option. Energy security will become an increasing issue. And, because so much of our agriculture is oil-intensive, food security too will be an increasing problem. (But not for Cuba who, when the Soviet Union collapsed, found itself without cheap oil and was forced to rapidly convert to a non-oil based, sustainable agriculture. Cuba now is largely self-sufficient in food and, by shifting much of its agriculture to organic production, has dramatically reduced its dependency on imported fuel and fertilisers, thus achieving much greater food security.)
Socially too we are living unsustainably. The gap between rich and poor grows. Poverty increases although enough food is produced to feed everyone on the planet - the problem is the poor cannot afford to buy it. 29,000 children a day die from preventable causes. Growing population is straining the ability of the earth to provide sufficient resources and the competition between nations for resources may well lead to conflict (eg Water Wars). This situation will be made worse if the projected increase in global population from 6.5 billion to 9 billion by 2050 occurs. Despite (or maybe because of) spending $1 trillion ($1 million million) per annum on 'defence' we don't feel secure. Perhaps diverting some of this spend to alleviating social injustice that fuels (though is not the sole cause of) international terrorism would be a better way of safeguarding national security.
Well, perhaps at least those of us living in the West are at least benefiting from a lifestyle that consumes the planet's resources disproportionately (for example, if everyone in the world was to live as the average European does, we would need 3 Earths to provide sufficient resources; for the US it would be 5 Earths). But research would suggest not. Over the past 50 years, we have got better homes, more money, longer holidays and, above all, better health. Yet research shows that happiness has not increased in the US, Europe or Japan.
In summary: We will soon be facing shortages of natural resources (oil, food, water), we may be bringing on climate instability, social divisiveness is increasing, and despite all this our resource intensive lifestyles are not even making us happier!