The EU isn't perfect, and ongoing reform to strengthen environmental rules is clearly needed. But the idea of leaving our precious environment in the hands of the current set of ministers fills me with terror.
There are many good reasons for Britain to remain a member of the European Union.
In a fast-changing world we need international rules to control big business and finance, and to ensure that people's rights are protected - at work and as consumers.
We also need to work across borders to meet global challenges - like the refugee crisis - head on.
But, for all the advantages of EU membership, none stand out quite so clearly as the European Union's role in protecting our environment.
In many ways, it's easy to see why working with our European neighbours makes sense. The threats our environment faces - from cross-border pollution, to overfishing in our seas and climate change - don't respect national borders, meaning that solutions must span the divide between nation states too.
Indeed, when it comes to protecting our environment, it seems to me that if the EU didn't already exist, we'd have to invent it.
But the EU isn't just good in theory. This week's Environmental Audit Committee report makes this clear when it says: "The overwhelming majority of our witnesses also believed that the UK's membership of the EU has improved the UK's approach to environmental protection and ensured that the UK environment has been better protected."
Right now, the effects of these changes in the law can be experienced across our country - on our beaches, in the countryside and in the air that we breathe.
I can see the environmental benefits every day
As an MP for a coastal community, I can see very clearly the effect of European rules in cleaning up our shoreline. In the 1970s, sewage blighted our beaches. In 1976, the European Union passed the Bathing Water Directive, which compelled countries to clean up their act - and thus decrease the pollution levels in the seas, which we all share.
The progress was slow at first but the results are now clear for all to see. By 1990, just over a quarter of our beaches met water quality standards. Now, with even stricter rules passed by the EU in 2006, over 97% of England's bathing waters have met the new minimum standard. Our beaches and seas are cleaner, and coastal economies have been given a boost, because of EU regulations.
It's also thanks to EU rules that some of the most precious wildlife and habitats in the UK has been protected. At the northern edge of my constituency are the South Downs - a splendid chalk hill landscape extending from Eastbourne to Winchester. On those hills, and across the UK's countryside, species have been protected by a variety of EU environmental laws.
The fate of British birds is a case in point. Analysis by the RSPB, BirdLife International and Durham University reveals that the most consistent single factor in a species' fate is whether it has the highest level of protection under the EU's Birds Directive or not. Some of the successes have been astonishing. Red kite numbers are up 2054%, cranes are up 1660% and marsh harriers are up 998%. Native British species such as the bittern and corn bunting are back from the brink of extinction.
And it's not just birds that are safeguarded under EU rules: the Habitats Directive ensures that bats, newts, otters, lizards and other species are guarded against overzealous development and destruction of the areas in which they live.
EU leading on climate change and air pollution
Another persistent reminder of the need for cross border rules is the air pollution crisis we're facing in this country, and the 40,000 deaths associated with it. Sources of air pollution are varied - the majority of the fumes comes from traffic in our cities, while some of the tiny toxic particles float across the Channel from France, carried by the wind.
Thankfully the EU's Clean Air Policy Package, which applies just as much to Northern France as it does to our own towns and cities - is forcing Government's like our own to clean up their act. Though they are reluctant, Ministers know that the threat of legal action looms if they don't reduce the levels of killer pollution in our towns and cities.
Coal-fired power stations in the UK - a longstanding source of pollution - have been shut down in the UK thanks to the EU's Large Combustion Plant Directive.
Precedent for such action exists in the shape of EU-wide action to tackle acid rain. Thanks to European laws this particularly damaging pollution - which threatened woodlands, river ecosystems and our own health - was cleaned up extremely successfully - meaning we saw a 90% fall in sulphur dioxide pollution since its peak level.
Of course it is the threat of catastrophic climate change which hangs over everything else we're doing to protect our environment. Surely there is no better reason to work with our neighbours than the need to tackle this complex cross-border catastrophe.
If we join forces with other countries, strengthening the EU-wide rules on carbon emissions that are already in place, then we have a chance of keeping future generations safe. Going it alone simply isn't an option for a challenge of this magnitude.
It's worth noting that it was the EU's political decision in 1990 to cap emissions of greenhouse gases by 2000 that formed the cornerstone of the 1992 UN climate convention. The climate and energy package, whilst being inadequate in its current form, has been a major factor in driving the deployment of renewable energy in the UK. Some of our dirtiest power stations have also been closed thanks to EU directives.
Not perfect on agriculture and fisheries - but it is getting better
As a former MEP, I am the first to admit that the EU has been far from perfect when it comes to protecting our environment. Some policies, such as the Common Agricultural Policy (CAP), have indeed had deeply damaging aspects. But CAP has also seen some improvements from a nature and conservation perspective and farmers are some of the most outspoken advocates for remaining in the EU.
Similarly the Common Fisheries Policy has not always worked well - a result of the policy itself, not the fact that it's common. Quota management in the EU began for the majority of commercial fish stocks with the first Common Fisheries Policy in 1983, a time when fish stocks were at extremely low levels and fishing pressure was still high.
Over time, fishing pressure has - slowly - decreased for quota species and some fish stocks are finally growing. The reformed EU Common Fisheries Policy (CFP) that became law in 2014 lays the foundations that could eventually lead to sustainable management of fish stocks in Europe.
Thanks, for example, to a Europe-wide campaign, and in spite of intense lobbying from the multinational fishing industry, we now have a ban on the hugely damaging practise of fish discards.
Though some European laws could clearly have been far better, rejecting the EU on the basis of not liking some policies would be to throw the baby out with the bath water. Indeed to think that things would be better if we weren't a member, seems to me to be somewhat short-sighted.
UK government's heavy hints to the future they plan outside
Of course it is impossible to know exactly what would happen if Britain left the EU but, when it comes to protecting our environment, the Government has dropped some heavy hints.
Ministers have tried their best to water down air pollution rules, the Chancellor has said that EU nature laws place "ridiculous costs" on British firms and, most worryingly of all, the government has been vigorously stripping away support for clean energy and renewable technology in the UK.
The UK government's role in putting a halt to EU wide fracking regulations should also serve as a warning - as should British MEPs being advised by the government to vote against legislation to oblige countries to carry out "routine and non-routine" inspections on vehicles' "real-world" emissions.
When it comes to EU proposals that fail to adequately protect the environment, we need to make sure we're pointing the finger in the right direction.
The EU isn't perfect, and ongoing reform to strengthen environmental rules is clearly needed, but we can only influence that by keeping our seat at the table. The idea of leaving our precious environment in the hands of the current set of ministers fills me with terror.
Only last week a detailed independent report on the subject concluded that leaving the union would be risky and could damage key green protections - and similar findings emerged in a landmark report by Institute for European Environmental Policy earlier this year.
Working with our neighbours to solve environmental problems
For challenges that span national boundaries, we need to work closely with other countries to solve them - to avoid duplication, increase co-ordination, and pool resources. Indeed if Britain is to ever be a world leader on protecting the environment, it will do so through the EU. As Tony Juniper, ex director of Friends of the Earth, noted: "We would never have had the impact we do as one country alone."
The EU can also provide a space for more radical ideas to develop and become mainstream while they're still off the radar of UK politics. Efforts to create a circular economy in Europe, for example, have the potential to be hugely beneficial by driving a radical shift of both consumption and production.
Ultimately, it's obvious that being part of the EU makes sense when it comes to protecting our environment. Pollution, threats to wildlife and environmental degradation don't respect national borders - so we clearly need shared solutions to the environmental challenges we all face.
The fundamental principle underpinning EU environmental regulations - that we need a level playing field across Europe to prevent a 'race-to-the-bottom', where member states seek to gain competitive advantage by destroying the natural environment - is more relevant than ever.
On June 23rd each of us is required to make an assessment about the UK's membership of the EU based on the best available evidence.
On that basis, if you're someone who cares about clean air, fighting climate change or protecting our wildlife, the case for putting a cross in the 'remain' box is overwhelming.
Caroline Lucas is the Green MP for Brighton Pavilion, and former leader of the Green Party. She is also a member of Environmentalists for Europe, a board member of Stronger In and a support of Another Europe is Possible.
Event: Caroline will be speaking at Friends of the Earth's event 'What has the EU done for the UK environment?' on Thursday 21st April. You can reserve your place here.
This article was originally published by openDemocracy under a Creative Commons Attribution-NonCommercial 4.0 International licence.