IEA projects that current energy trends will lead to a 3.6 °C rise in Earth's temperature

The World Energy Outlook 2012 just released by the IEA makes for fascinating reading.

Primary energy demand

First of all the IEA projects global energy demand to increases by over one‐third between now an 2035 driven by emerging economies. There are projected to be dramatic shifts in the energy mix as collective share of oil and coal drop by fifteen percentage points to 42%.  However, because of increased use of natural gas fossil fuels remain the principal source of energy worldwide.  Unconventional gas (shale gas) is projected to surposs coal in the primary energy supply mix by 2035.

The United States, which imports about 20% of its total energy supply, is projected to become nearly  self‐sufficient in net terms by 2035, primarily because of unconventional oil and gas, bioenergy, and improved fuel efficiency in transport.

Large‐scale investment in energy‐supply infrastructure is required.  It is estimated to amount to about $37 trillion over 2012‐2035, which is equivalent to 1.5% of global GDP.   Of this the oil and gas supply infrastructure will require $19 trillion; while $17 trillion will be required by the power sector for generation, transmission and distribution.

Electricity

Demand for electricity is projected to grow by over 70% to almost 32 000 TWh by 2035.  Over half of the increase is projected to come from China and India alone.  Generation from renewables globally is projected to grow  from 20% to 31% of total generation.

Water and energy

Global freshwater use for energy production in 2010 totalled 583 billion cubic metres (bcm), or some 15% of the world’s total water use. Of that, water consumption – the amount used but not returned to its source – was 66 bcm.  It is projected that water use will increase by 20% over 2010‐2035 (compared to 70%  more energy production), while consumption will increase by 85%.   These trends are the result of more efficient power plants with advanced cooling systems that reduce overall water use but increase consumption.

Energy efficiency

Several major energy‐consuming countries (China, United States, the European Union and Japan) have adopted new energy efficiency measures over the last year.  Implementation of these programs is projected to reduce global energy intensity (energy consumption per unit of GDP) by1.8% a year through to 2035.  This is a major improvement compared with only 0.5% per year over the last decade.

The buildings sector is singled out as having tremendous potential for energy efficiency gains (one third of the world's total energy consumption is by buildngs), but four‐fifths of this are not projected to be realized, primarily due to non-technical barriers.

Emissions

The IEA projects that energy‐related CO₂ emissions will rise from an estimated 31.2 Gt in 2011 to 37.0 Gt in 2035.  It is estimated that this would result in a long‐term average temperature increase of 3.6 °C at the Earth's surface.

The IEA has investigated an alternative scenario which if implemented could result in a lower estimated temperature rise at the Earth's surface.  The "Efficient World Scenario" assumes a more efficient allocation of resources which will increase global economic output by $18 trillion by 2035.  It requires an added investment of $11.8 trillion in efficient end‐use technologies.   This investment is projected to be  more than offset by a $17.5 trillion reduction in fuel bills and a $5.9 trillion cut to supply‐side investment.

In this scenario global primary energy demand growth is halved compared to the most probable scenario.  Energy intensity is assumed to improve at 2.6 times the rate over the last 25 years.  It is projected that oil demand will peak before 2020 and decline through 2035,  Coal demand in 2025 is projected to be lower than today. Natural gas demand is projected to continue to increase but at a lower rate than currently projected in the most probable scenario.

As a result, energy‐related CO₂ emissions are projected to peak before 2020 and decline to
30.5 Gt in 2035.  The IEA estimates that this would result in a long‐term average temperature increase of 3 °C.