Perhaps the most damaging effect of petrochemicals is global warming. The use of fossil fuels releases carbon dioxide and methane, two greenhouse gases that trap the Earth’s heat within the atmosphere, leading to warmer oceans and climates, unstable weather, rising sea levels, flooding, drought, changes in water flow, declining amounts of potable water, forest fires, famine, species extinction, and pressure on species to adapt, among other things. These changes are not going to take place immediately – they will occur over decades. However, they will gradually increase in occurrence and severity, and will require ongoing mitigation and response.

The projected effects of climate change are sufficient reason by themselves for us to seek to reduce fossil fuel dependency wherever possible. However, Peak Oil will challenge our ability to deal with and adapt to global warming: a decline in global oil supply paired with an increase in the cost of goods and services reduces our ability to make the investments in infrastructure that are required in order to respond to global warming in a proactive and coordinated fashion. Therefore, it is imperative that we consider proposed responses to Peak Oil and global warming in tandem.

Since the Industrial Revolution, the average global temperature has increased by about 0.7 degrees Celsius, and scientists expect further warming of 1.4 – 5.8 degrees. The United Kingdom recently published a report stating that a global temperature increase of even 2 degrees Celsius might be too high and result in severe irreversible effects, some of which are already beginning to appear. As drought, famine, and flooding increase, we will need increased financial and energy resources to repair the damage.

Further into the future, we will experience the drastic effects of glacial melting, regions of the globe will become more arid, and weather patterns will become harsher. However, with less oil available (potentially none at all) and at increasingly higher prices, poorer countries will not be able to deal with these issues, and more well-off countries will be less reluctant to help as resources will be scarce and increasingly expensive. Economically, the world will be less able to deal with the negative impacts of global warming after reaching Peak Oil, since we will have less and less of the abundant, cheap energy to which we have become so accustomed and which allows us to respond to crises with appropriate and necessary resources and efficiency.