London Gatwick Airport, already known as Europe’s busiest single-runway airport, is set for a massive transformation after receiving official approval to build a second runway. The decision, announced by UK Transport Secretary Heidi Alexander over the weekend of September 21-22, 2025, marks a pivotal moment in the ongoing debate over airport capacity, economic growth, and the UK’s climate commitments.
The £2.2 billion project, which is expected to be completed by 2030, involves moving Gatwick’s northern runway—currently used only for taxiing or as a backup—12 meters to bring it into regular operation. This engineering feat will allow the airport to handle more than 100,000 additional flights each year, potentially raising annual passenger numbers from 43 million today to 75 million by the end of the decade, according to The Guardian.
Matt Thomas, chief executive of Ports of Jersey, welcomed the decision, calling it “a significant milestone in investment in constrained London airport capacity.” He added, “The prospect of additional landing and take-off slots should enable airlines to be more efficient and schedules more reliable, as well as adding opportunities for growth in route networks.” Thomas also emphasized the potential positive impact on Jersey’s connectivity and wider economy, saying, “We look forward to the opportunities this expansion will bring to our community, to the island’s connectivity and our wider economy,” as quoted by BBC Jersey.
Airlines serving the Channel Islands have echoed these sentiments. Aurigny, Guernsey’s main airline connecting the island with London, described the approval as a boost for its services. “As a key partner in connecting Guernsey with London and onwards to over 230 destinations worldwide, we see this expansion as a positive step which will ultimately provide enhanced flexibility throughout the year to further optimise schedules for the island,” an Aurigny spokesperson told BBC Guernsey. The airline expects the new runway to reduce delays and deliver more reliable, efficient service for its passengers.
But the path to approval was anything but straightforward. Back in February, Alexander had signaled she was “minded to approve” the plan, despite initial recommendations for refusal from planning inspectors. The government’s final green light came with conditions—most notably, the requirement to encourage passengers to use trains rather than cars to access the airport, and provisions for noise insulation or compensation for affected local residents. Gatwick, for its part, agreed to some of these measures but is still reviewing the fine print, especially as public transport quotas appear to have been reframed as targets rather than strict obligations, according to The Guardian.
Gatwick’s expansion is just one piece of a much larger puzzle. The government has also signaled support for Heathrow’s proposed third runway—a vastly more expensive undertaking, with estimates running to £21 billion for the runway alone and up to £48 billion for the full expansion. Yet, as Chancellor Rachel Reeves pointed out, the Gatwick project is “in addition to our commitments to a third runway at Heathrow,” with Labour prioritizing economic growth through infrastructure investment. The Airports Commission had previously suggested that only one additional runway should be built in southeast England, but Gatwick’s plan, which essentially upgrades an existing emergency runway, has been positioned as a more modest and less disruptive alternative.
The economic arguments for Gatwick’s expansion are robust. The airport claims the scheme will create 14,000 jobs and contribute £1 billion annually to the regional economy. Chancellor Reeves has said the plans would create thousands of jobs and bring in billions in investment. Supporters, including London Mayor Sadiq Khan, see the expansion as a necessary hedge against Heathrow’s much larger and more controversial project. Proponents also argue that increased air links underpin wider trade and that outbound tourism, far from being a drain, generates £52 billion in gross value added each year and supports over 800,000 UK jobs, as noted by the travel association Abta and reported by The Guardian.
However, the environmental stakes are high. The UK has legally binding targets to reach net zero emissions by 2050 and must limit average global temperature rise to 1.5°C to avoid catastrophic impacts from climate change. The UK government has, for the first time, included international aviation in its carbon budgets from 2033 onwards. That means decisions to expand airports like Gatwick could have a significant impact on the country’s ability to meet its climate goals, as highlighted by BBC News.
Emissions from flying rose by 9% last year, driven largely by growing demand for international leisure travel—the very market Gatwick primarily serves. The UK’s climate watchdog, the Climate Change Committee (UKCCC), has warned that emissions from aviation “pose a risk to the UK’s emissions targets.” While the UKCCC hasn’t ruled out airport expansion altogether, it has cautioned that the government should consider measures to reduce demand for flights.
To square this circle, the government is banking on rapid advances in technology and alternative fuels. Sustainable Aviation Fuels (SAF) are expected to play a central role. These fuels, derived from waste oils, crops, or even captured carbon dioxide, can offer lower emissions than traditional fossil fuels—though their environmental benefits vary widely depending on their source and production methods. Currently, only 2% of jet fuel supplied in the UK must be sustainable, but that mandate will rise to 10% by 2030 and 22% by 2040. A bill before Parliament aims to guarantee a minimum price for SAF, encouraging investment but likely raising ticket prices as costs are passed on to consumers, according to BBC News.
Yet, even with these measures, the environmental math is daunting. The UKCCC projects that net CO2 emissions from SAF will decrease by about 1% a year, while flight numbers are expected to grow by 2-3% annually. More radical solutions, such as hydrogen-powered or electric aircraft, are still years away from commercial viability and would require sweeping changes to airport infrastructure and energy supply chains.
Environmental groups, including Greenpeace UK, have voiced strong opposition to the expansion, citing increased air pollution, noise, and carbon emissions. Ruth Cadbury, chair of the Commons transport committee, summed up the mood of skepticism: “They continue to say they are committed to reducing carbon emissions, but we are waiting for them to show us how they will square the circle of doing so while enabling thousands more flights.”
For local residents in Sussex, the prospect of more aircraft noise and congestion is a major concern. Gatwick has pledged to pay for highway improvements and offer compensation to those most affected, but the debate over the social and environmental costs of expansion is far from settled.
As Gatwick prepares to move forward with detailed design work and construction, the airport’s second runway stands as a symbol of the UK’s struggle to balance economic ambition with environmental responsibility. The coming years will reveal whether this high-stakes gamble pays off for both the economy and the climate.
