The current energy crisis in Europe is an acceleration of the underlying trends. With Russia's invasion of Ukraine putting prices up, nations are rushing to reduce their dependence on gas.

But the need to get off fossil fuels was already there, and already at a crisis point. There are clear signs of global heating around us, with climate breakdown causing floods and fires. This should not make us feel powerless, because it simply points up the urgency of decarbonization.

This supplement looks at three pieces of the puzzle from the viewpoint of the tech industry.

• The trouble with data center energy figures Why we need better numbers to forecast energy use - and how we can get them
• Don't look to the past for tomorrow's efficiencies We've made vast improvements, but it can't go on forever
• Self-sufficient cell towers Remote cellular network equipment could be the earliest to transition