There is no longer any need to prove the point that technology has a major role to play in reducing carbon emissions ­ not least since the publication of figures indicating that IT is responsible for two per cent of global CO2, the same level as the headline-grabbing airline industry.

But IT suppliers are making a good show of rising to the challenge. There are plenty of green systems already on the market, and more in development.

But technology on its own will not be enough.

Green IT is not only about spending money on new systems. There also needs to be significant cultural changes, amounting to much more than simply encouraging people to turn off their PC at night or not to print emails unless really necessary.

With the development of carbon-tracking technologies, real-time power monitoring and smart building systems, the IT department has a major role in shaping an organisation’s environmental policy.

But even before the next generation of systems becomes widely available, the inclusion of environmentally-friendly considerations in commodity IT purchasing is far from mainstream.

And with a possible economic downturn looming, businesses are warier than ever of the seemingly-endless green credentials being touted by suppliers.

It is here that the government may have a significant role to play, and without recourse to meddlesome regulation.

With annual IT spending power of a massive £14bn, the inclusion of green criteria into public sector technology procurement would have an enormous effect, by setting an example and stimulating the market.

There is no question that the basic remit of the Office of Government Commerce ­ Whitehall’s buying agency ­ should remain ensuring the best possible deal for taxpayers’ money. But such a remit does not have to be to the exclusion of all other considerations.

Public sector technology must be up to the job. And ensuring a minimal environmental impact is now part of that job.

Apart from the flaring of the identity cards debate in the aftermath of the data loss scandals, it has been a quiet time in the world of government technology.

It had been a busy few years. High-profile, high-value, high-risk programmes, usually at a national level, seemed to be kicking off every other week ­ £4bn for the defence information infrastructure, £12bn for a digitised health service, £2bn for joined-up justice, to name just three.

Then the changeover of prime minister dropped a blanket over everything, muting future plans both for the six months beforehand and the eight months since.

Tony Blair might have, famously, not been able to use a PC. But there was a clear sense throughout his premiership that the man at the top was broadly behind all that was high-tech, modern and new.

But a change of mood is not all about personality. It is also about money.

Even before the threat of global recession, the Comprehensive Spending Review (CSR) was following up on the easy wins of the Gershon report’s efficiency targets with swingeing year-on-year savings requirements.

Yet despite the recent lack of mega-procurements, there is still plenty going on behind the scenes ­ mostly to try to match CSR targets and calls for citizen-centric service improvements.

It is also possible that the public sector has finally learned the single most important lesson about how to avoid IT disasters ­ don’t make such a song and dance about it.

Arguably, the biggest failure of the NHS IT programme was to give itself a name and draw itself a timetable. A PR failure has created a PR disaster, while back in the real world there is no option but to modernise and there has been some progress.

Sir Ronnie Flanagan’s review of policing makes thoroughly sensible statements on the potential for mobile technology and for centralised procurement. So far, at least, the government has avoided the traditional response of creating a bounded, timetabled, inflexible central IT programme.

Fingers crossed it will stay that way.

It’s about advertising. It’s about search. It’s about Microsoft trying to take over the world. The $44.6bn (£22.4bn) offer for Yahoo has been cast in many lights since hitting the headlines last week .

Online ads are certainly a big draw ­ worth $40bn (£20bn) last year, and expected to double to $80bn by 2010. And search is one of the main ways to tap the market.

Hence the involvement of Google, which delivered 56 per cent of global searches at the last count, and which is sufficiently keen on keeping Microsoft out of the game to be banging hard on the anti-competition drum and, reportedly, in talks with Yahoo itself.

But there is also a longer game behind Redmond’s proposal, which offered Yahoo shareholders a 62 per cent premium despite stock value falling consistently since October.

The deal is not just about Microsoft trying to extend its dominance into new markets, it is also about protecting the core business.

In his speech at the Institute of Directors last week, Bill Gates made much of the future of software as a service (SaaS) ­ that is, applications no longer held individually on a PC or server but accessed in real time over the internet.

Google launched its online Google Apps service for business last February, and has at least one major consultancy offering it to corporate clients.

Assuming Gates is right and SaaS is the future, then Microsoft needs to take its desktop software onto the internet as fast as possible or it will lose the initiative.

All of which leads to a conclusion that offers some cause for cheer.

Not only is it simplistic to dismiss the Yahoo bid as another sign of Microsoft’s overweening dominance. It is also too easy to consider the bid’s success as another nail in the competitive coffin.

In fact, the reverse may be true. Neither Microsoft nor Google has any real rival in their respective spheres.

Anything that brings them into direct competition could finally provide long-suffering consumers and IT managers with a genuine choice.