Over the past two decades, ICE has strategically positioned our energy business for the energy transition. Our long-term strategic direction, and the value of the diverse, deep and liquid markets we operate, contributed to the record volumes we saw across our energy markets in 2021, including in Brent, TTF natural gas and our global environmental complex. As we look to 2022 and beyond, the breadth of our global energy platform will enable us to continue to benefit from the secular tailwinds emerging across the energy complex, including the globalization of natural gas and the inevitable transition to clean energy.
These are trends that ICE began investing in over a decade ago with our acquisition of the Climate Exchange in 2010. Today, cleaner energy sources, including our global natural gas and environmentals businesses, make up 40% of our energy revenues and have grown 15% on average over the past five years.
The global energy crisis in 2021, rooted in soaring demand and disrupted supply, was a peek into the future of what the energy transition could look like in the decades ahead. Energy consumption is expected to more than double over the next thirty years, yet carbon emissions are expected to be reduced by half. This imbalance in supply and demand will introduce additional complexity and volatility to energy markets and drive greater demand for risk management across the energy spectrum, an area where ICE excels.
In 2021, we achieved record volumes in our European gas contract, known as TTF, which increased 45% year-over-year, and drove revenue growth of 39% versus the prior year. Volatile gas and power markets drove customers to our markets to help manage their risk but, more importantly, the globalization of gas has driven TTF to emerge as a global benchmark for gas. This secular trend has contributed to strong growth across our European & Asian gas complexes including 43% average revenue growth over the past five years. As the number of participants in these markets continues to grow, we see these trends continuing to favor our growing global gas complex well into the future.
Trading alongside our global oil, gas, and power markets, our environmental markets provide customers price transparency across the energy spectrum that is critical in navigating the clean energy transition. Increased risk management in carbon pricing drove record volumes across our environmental complex in 2021, including in our EU, U.K. and California carbon allowances, as well as our Renewable Greenhouse Gas Initiative allowances. While these markets are still maturing relative to our benchmark oil and gas markets, we believe our leading position, and the breadth and depth of our broader energy platform, sets us up to continue to benefit from the trend of sustainability and net-zero carbon commitments.