Shell’s latest energy scenario, Sky, illustrates the choices and challenges required to achieve net zero emissions in just 50 years, including how to tackle emissions from industry and agriculture.

As a society, we must limit the buildup of carbon dioxide in the atmosphere and see a fall in the level of other greenhouse gases such as methane.

In the case of carbon dioxide, Shell’s Sky scenario shows that switching from coal to natural gas and then to renewable technologies like wind and solar could, over time, decarbonise much of the world’s electricity. However, for industries such as cement manufacture, iron ore smelting and the production of chemicals, the task is even more challenging. Making cement requires temperatures of around 1450°C. This heat is delivered by burning coal or natural gas, which produce carbon dioxide emissions. And the conversion process itself also releases carbon dioxide.

The challenge is that many critical industries require intense heat, and only fossil fuels can generate that heat.

In Sky, the solution to these industrial challenges includes:

  1. Making the processes more efficient. This is applied today but it isn’t a net-zero strategy.
  2. Seeking alternatives or recycling existing stock. This is beginning to happen but requires greater scale.
  3. Directly managing carbon dioxide is the ultimate step, either permanently storing it underground, or through a fundamental change in the underlying processes that could eliminate carbon dioxide emissions.

One example where a fundamental change is on the horizon is the manufacture of iron ore for steel.

Today coal is required in the manufacture of iron-ore. In the future, this coal could be replaced by hydrogen gas. If the hydrogen could be made at scale through the electrolysis of water using electricity from renewable sources, then society could have emissions-free iron. There is not a single facility in the world that does this today, but plans are in place for a first demonstration project1. Scaling up new technologies like this will take time, but during the second half of the century they could replace existing industries, eliminating carbon dioxide emissions.

Where local solutions may be difficult or expensive to implement, industries could look towards carbon markets. These markets could link ongoing emissions with so-called “negative emissions technologies” such as biomass energy with carbon capture and storage and achieve an overall net-zero outcome.


Reducing methane emissions from the agricultural sector could be even more challenging.

Clearing forests for cattle releases carbon dioxide and grazing cattle belch methane, a much more powerful greenhouse gas. Growing rice in a paddy field also leads to methane emissions. The scale of such agricultural emissions, combined with methane from the oil and gas industry, is raising the level of methane in the atmosphere and adding to warming. Unlike carbon dioxide, which collects in the atmosphere, methane has a shorter life. So, reducing methane emissions would lead to a fall in its atmospheric concentration. For agriculture this could be achieved through changes in farming practices such as what farmers feed their cattle. Society could also encourage consumers to change their diets and reduce demand.

And we should not forget that agriculture can also act as an important sink to collect and store carbon dioxide.

Changes in tilling and grazing patterns increase the carbon content of soil, keeping the greenhouse gas out of the atmosphere. Agriculture could either help or hinder the world to achieve the Paris Agreement and the global dissemination of best practices could make a real difference.

Read the Sky publication to see how the goals of the Paris Agreement could be met through a combination of technology, government policy and societal actions.

Could society achieve the goals of the Paris Agreement? What do you think?

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Download Sky Scenario

The Sky scenario illustrates a technically possible, but challenging pathway for society to achieve the goals of the Paris Agreement.

Shell and the energy transition

Shell scenarios are not the Shell business plan nor a policy proposal. To find out what Shell is doing to thrive through the energy transition click here.

For over two decades Shell scenario thinking has incorporated the issue of climate change. The Sky scenario joins two previous Shell scenarios, Mountains and Oceans that saw rapid decarbonization but fell short of the goals of the Paris Agreement. To achieve the goals of the Paris Agreement, the Sky scenario relies on a complex combination of mutually reinforcing actions by society, markets and governments. It adopts an approach grounded in current economic and policy development mechanisms, but then progressively becomes ‘goal-driven’ to achieve society’s ambition for net-zero emissions by 2070. At Shell, we hope it’s a helpful contribution to one of the world’s toughest challenges. You can explore all three scenarios at

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