Oil and gas were the most expensive, but it wasn’t until the 1970s that prices began to fall.
Today, the cost of oil and gas is around $100 per barrel.
The world’s petroleum production was around 17 billion barrels in 2015.
The global economy, on the other hand, is estimated to have grown to around $1.3 trillion in 2015, up from $1 trillion in 2012.
The key drivers of the growth in the world economy are the economies of the Middle East and Africa, the South-East Asia and the West.
The growth in world GDP over the past decade has been fuelled by the increased use of energy in the economies and populations of the West and the developing world.
Oil has become the second most important energy resource in the global economy behind natural gas.
This means that oil and natural gas are becoming increasingly important for the economies in developing countries and other parts of the developing global economy.
As part of its global energy strategy, the European Union (EU) is set to invest a record €2.8 trillion in the energy sector.
This includes a €1.7 trillion ($1.4 trillion) investment in new oil and shale gas fields in North America and Europe.
The European Union also plans to invest an additional €1 trillion to expand its renewables sector.
In the last few years, the EU has set up a special committee to look at the energy and climate risks associated with climate change and the impact that this is having on the economies, populations and societies.
In this context, the new report on energy and carbon emissions from fossil fuels by the European Commission (EC) will be released in October 2017.
On the energy side, the report reveals that in the last decade, world oil production has risen by 2,700 to 3.4 million barrels per day (bpd), which is about three times as fast as in the 1980s.
This has seen the price of oil fall by 30 per cent from the year 2000.
The price of natural gas has also fallen by 70 per cent, while the cost per barrel of crude oil has dropped by 60 per cent.
According to the EC, the world is now a net exporter of oil, natural gas and other energy products, with the exception of China and India, where oil and the carbon dioxide emissions are the main drivers.
But the main driver behind the rapid growth in global oil production and the global economic slowdown has been the oil price collapse.
During the 1980-1990 period, prices were higher than they are today.
The decline in oil prices has been largely due to the collapse in the price for crude oil.
The fall in the prices of oil has made it difficult for producers to invest in new wells and to drill new oilfields.
This makes the production of oil more expensive than it was in the past, because the new wells are not as productive.
It is not only the economic slowdown that has had a significant impact on the world oil market.
In addition to the oil prices, many countries in the developing and middle-income countries have been hit by the drop in oil production due to climate change.
“The world is seeing a very different picture from what we saw when oil prices were high.
We are seeing a much more serious global economy and the development of climate change are also causing a lot of concern,” said Prof John Soutphommasane, a climate change expert at the University of Sussex.
While the global energy sector is now in decline, many nations are still using fossil fuels.
For example, the UK is using more than 30 per year to keep the lights on, the equivalent of the entire yearly output of the UK.
In India, the country that is currently the world leader in renewable energy, coal and nuclear power use more than 20 per cent of the country’s energy, while natural gas, hydroelectricity and wind power account for just a quarter.
India is also one of the most carbon-intensive countries in world history, emitting more greenhouse gases per capita than the UK, the US and Germany combined.
“The climate change issue is the reason that people are increasingly concerned about the sustainability of the oil sector, which is responsible for 80 per cent to 90 per cent [of global CO2 emissions],” said Prof Soutpommasana.
Prof Soutbommasanes comments come just months after a report by the United Nations Environment Programme (UNEP) found that the world population is increasing by nearly two million people a day and that there is a global increase of 0.8 per cent in the number of people living in extreme poverty.
Dr Soutpotommasano said that the rise in oil and carbon pollution are the major factors behind the increasing concern among policymakers about climate change, and the rise of the extreme poor in many countries.
“There is a growing awareness in the United States of the need to invest heavily in developing