When the people of Hamburg voted a year ago for climate neutrality by 2040, the matter seemed clear. Some celebrated the referendum on October 12, 2025 as a historic step for climate protection. The others warned of billions in costs, bans and social upheaval. Twelve months later, neither has happened. The stricter climate law applies, but there has been no major change. Hamburg has neither become noticeably more climate neutral, nor are the feared consequences for tenants, drivers or companies visible. The city is faced with the question: What will happen next year?
Because: The sharpest instruments of the so-called future decision are yet to come. Since the beginning of 2026, statutory maximum amounts for the city's annual CO2 emissions have been in effect for the first time. Whether Hamburg sticks to these budgets will become clear in the summer of 2027. The Senate must present an estimated balance sheet by June 30th. Then it becomes visible whether the targets have been torn. If the limit is exceeded, the Senate would have to decide on measures within five months to compensate for the deficit, according to the requirements of the Climate Protection Act.
The Senate has so far left it open what exactly would happen. According to the environmental authority, “a wide range of measures” are being examined. The authorities are currently preparing for the next update of the climate plan. At the same time, the Senate points out that an immediate program can only contain measures that are actually within Hamburg's own regulatory authority.
At the end of June, the environmental authority published such an estimated balance for the first time, which was introduced as a direct result of the stricter climate protection law. Its purpose: to make it clear much earlier than before whether Hamburg is making progress or falling behind in climate protection. The first result was sobering. For 2025, the balance showed CO2 emissions of 12.037 million tons. Compared to the previous year, this corresponded to an increase of 2.6 percent. Since 1990, Hamburg has reduced its emissions by 41.3 percent. However, the city is still a long way from the legal interim target of a 70 percent reduction by 2030.
According to the environmental agency, the reasons for the increase from 2024 to 2025 lie primarily outside of classic climate policy. A colder winter caused the consumption of natural gas and coal for district heating to increase, and the economic recovery increased companies' energy needs. There is also an effect that makes the contradictions of the transformation visible: with the increasing electrification of transport, electricity consumption initially increases. At the same time, the decarbonization of the federal electricity mix was weaker than in previous years.
District heating was able to reduce its CO2 footprint. According to the environmental authority, CO2 emissions per kilowatt hour there fell by around 13 percent within a year. Greater use of industrial waste heat as well as additional waste heat from the Borsigstrasse waste recycling plant are responsible. However, the effect was not enough to offset the overall increase in energy consumption in Hamburg.
For the initiators of the referendum, the results above all confirm their criticism of the Senate's current pace. “The increase in emissions in 2025 represents an unexpected low point and should have been the turning point for the Senate,” says Annika Rittmann, spokeswoman for the Zukunftssentscheid initiative. The estimated balance now makes visible for the first time what critics have complained about for years: the gap between the goals we have set ourselves and the actual progress.
It should be mentioned that the first estimated balance does not yet have any immediate consequences. The new emissions caps did not yet apply for 2025. They only took effect at the beginning of 2026. The actual stress test of the referendum is therefore still pending. It will become clear for the first time next summer whether Hamburg will adhere to the legally prescribed emissions path or whether the Senate will be forced to make adjustments.
“The federal political developments are of no help to Hamburg at the moment”
At that point at the latest, a conflict that is already becoming apparent today is likely to come into focus. The environmental authority and the transport authority repeatedly point to framework conditions that Hamburg cannot determine itself. In the transport sector, the decisive levers are the electrification of the vehicle fleet and a more climate-friendly electricity mix. The discussion about the end of combustion engines and the lack of cheap electric cars has recently slowed down change. The Senate also sees the federal government as having a duty to expand heat pumps and heating networks.
“The federal political developments are currently of no help to Hamburg,” says the environmental authority. More reliable framework conditions for heat pumps, faster approvals for heating networks and competitive electricity prices are needed. The transport authority also refers to funding programs and tax incentives that only Berlin can offer.
This is exactly what the initiative sees as a problem. “Instead of accepting the voters’ clear mandate, the Senate is shifting responsibility to Berlin,” says Rittmann. The city has not yet provided an answer to the actual core problem. “To date, the Senate has not communicated a plan for the ambition gap that has accumulated over the years.”
In its latest climate plan interim report, the environmental agency assesses the prospects for industry, commerce and private households comparatively optimistically. The transport sector, on the other hand, is seen as a problem child. Additional measures are necessary there in order to achieve the intended reduction targets. The Senate already sees the greatest need for action in precisely the area in which climate policy has a direct impact on the everyday lives of Hamburg residents.
Switching to electric cars would help
The transport authority still relies primarily on technological solutions. The key to reducing emissions lies “not in driving bans or other restrictions, but in the drive transition and the electricity mix”. Hamburg already has the highest proportion of electric cars and plug-in hybrids among the federal states. In addition, the charging infrastructure is being massively expanded. 10,000 charging points should be available by 2030. At the same time, the authority points to increasing passenger numbers in the HVV, falling registrations of private cars and growing bicycle traffic.
Environment Senator Katharina Fegebank also sees Hamburg on track. “Climate neutrality by 2040 is an extremely ambitious goal and a huge project for an industrial and port metropolis like Hamburg,” says the Green politician. The voters' mandate was accepted. The first balance sheet is available and the course is now being set for the next update of the climate plan and climate protection law.
Fegebank speaks particularly openly about the uncertainty of the process. “We don’t know the end, but we are on the way – even if we don’t yet know every single step until 2040 on the drawing board,” she says. For the senator, this is not an expression of lack of plans, but rather an attitude that she got to know during a visit to Copenhagen and that she is also striving for in Hamburg.
This is exactly what the referendum will have to be measured against in its second year. The vote is decided, as is the goal. What is now unclear is less whether and more about how. When the next estimated balance is available in summer 2027, it will become clear whether Hamburg adheres to the new emissions path or has to make adjustments for the first time. The question will then become louder as to whether the biggest obstacles are actually in Berlin - or on our own doorstep.
Editor Julia Witte known as Vedder works in the Hamburg editorial team of WELT and WELT AM SONNTAG. She has been reporting on Hamburg politics since 2011. One of her main focuses is environmental policy. She is co-chair of the Hamburg State Press Conference, the association of state political journalists.
