A mountain slope collapses. It's too hot. The permafrost（[地]永久冻结带） is melting. The cause is the rise in greenhouse gases. CO2 emissions need to be cut. Much more quickly than has been planned.

  More and more court rulings（裁定） are calling for that. The Zondblich Observatory（天文台） is perched（ 栖息） more than 3,000 metres up in the Hoa Taouen National Park in Austria. Here, scientists are studying weather and climate change. This building dates back 135 years and has withstood snowstorms and gale force winds so far. Elke Ludovig and Mark Orlefs are doing important work up here. With dozens of measuring devices, the climate researchers are recording the rise of greenhouse gases in the atmosphere.

  The temperatures here have already risen on average 2 degrees Celsius, with knock-on effects. This is the northern terrace of the Zondblich Observatory. Here in particular and on the northern flank（侧面）, you can clearly see the effects of climate change up here in the mountains and the measures and adaptations（适应） needed to protect this infrastructure. There's a lot of concrete under here. The entire terrace is concreted over so no water can penetrate. The concrete posts are also shoring up the mountain peak（山顶）.

  The reason for all these measures is climate change. Permafrost normally holds together the mountain's interior（内部）, but it's melting. 200 iron bolts and a steel net now stop the mountain from crumbling（弄碎）. Although the observatory is far from any industry or other greenhouse gas emitters, the researchers are finding that carbon dioxide concentrations keep on rising. Here at Zondblich, but also at the other end of the world, at Maua Loa Observatory on Hawaii（夏威夷）, for example. It's the same problem everywhere.

  The curve from Maua Loa is amazingly similar. Measurements there were started in 1958, under the world's longest running. We now have 420 ppm. That's 0.04% CO2 in the atmosphere, almost the same as in Hawaii. It clearly shows it doesn't matter where and when CO2 is emitted, it's globally distributed super fast. That also means the Earth will only stop heating up when CO2 emissions drop worldwide.

  That's precisely what happened during the COVID pandemic and was measurable at Zondblich. The global shutdown in the pandemic led to a drop of about 6% of global CO2 emissions. To reach the Paris Agreement's goal, we'd need to cut emissions by 6% every year between now and 2050. That shows just how dramatic the reduction is that's needed. Time is pressing. The EU aims to become climate neutral by 2050.

  With net（纯粹的） zero emissions, it remains unclear how that is to be achieved. Climate change is creating anxiety. Fears felt by Martina Dopin, the 27-year-old decided to fight back. With other climate activists（积极分子）, she filed a suit against an oil multinational, its logo, a seashell. We won the court case against one of the biggest polluters of the world, Shell, a Dutch（荷兰人） company, which is super powerful. We showed that the movement is actually more powerful and that this is the point of return actually that we are kind of starting to win.

  Shell's core business is oil and petrochemicals（石化产品）. Fossil fuels release millions of tonnes of CO2 when they combust. In May 2021, a court in The Hague ruled that Royal Dutch Shell had to reduce its CO2 emissions by 45% by 2030. It was a legal sensation（感觉）. Also for Donald Pols, a co-plaintive（悲哀的）. Martina Dopin meets him on the Dutch North Sea coast.

  Donald Pols is head of the environment organisation Milleur Defencee. The judgement is the first in the world which calls upon a company to curb（控制） its greenhouse gas emissions. To be honest, the whole court case would not have been possible if it wasn't for people like you and the 17,000 other co-plaintives, the people that financially supported it with more than half a million euro. Shell is appealing the ruling. But the judge's message is loud and clear. It has set a precedent（先例）.

  Worldwide, there are about 1,000 such claims pending. Is fighting climate change in the courts an opportunity to make real progress? Martina Dopin thinks so. What drives me as an activist is that we see the effects of climate change everywhere for a very long time already, especially in the global south. We see floodings in Mozambique, the oil spills in Nigeria, the heat waves in USA, in Canada, and yet we still don't know anything. Policymakers are failing to act, so there's a lot of activism needed.

  And now it's also coming closer by. At the moment, there are big floodings in the south of the Netherlands（荷兰（西欧国家）） and in Germany. People are missing, people are dying. In July 2021, extreme rainfall and catastrophic（灾难的） flooding the worst in many, many decades had devastating effects in western Germany. Many people were made homeless for months. More than 170 people died.

  Hundreds were injured and many had to be evacuated（疏散）. Residents lost their homes and their livelihoods（生计）. A few days earlier, the US and Canada had seen temperatures of over 50 degrees Celsius. Fires destroyed residential（住宅的） estates and entire villages. Dozens died of heat exhaustion. Climate change is making extreme weather events like this more frequent.

  For over 30 years, scientists have been raising the alarm and urging a major rethink. Before the pandemic, hundreds of thousands of young people held climate protests that hit the headlines. Yet no major policy changes were forthcoming（即将来临的）. Then in April 2021, Germany's Constitutional（保健散步） Court in Karlsruhe declared the Federal Climate Change Act unconstitutional in parts. The top judges said it particularly violated（违反） the younger generation's right to freedom because if current measures were too lax（松的） now, they would lead to disproportionate（不成比例的） costs after 2030. These future obligations to reduce emissions have an impact on practically every type of freedom because virtually all aspects of human life still involve the emission of greenhouse gases and are thus potentially threatened by drastic（激烈的） restrictions after 2030.

  It is the most far-reaching top-court ruling on climate change in the world. Freedom is also the freedom of future generations and the freedom of all the people worldwide, the need to counterbalancing（ 起平衡作用） over time. That's a sensation. Felix Eckhard co-represented the case. The law professor is the director of the Research Unit Sustainability and Climate Policy in Leipzig. He can see the impact of climate change in the city's Aalwald Forest.

  The droughts of recent years are endangering ash（灰） trees and sycamore maples, but the expert says it's not just the woods' future that's in danger. Climate change threatens to destroy democracy's physical foundations. Climate crises, wars, water shortages and mass migration（迁居） will leave little behind of our free lives or even of symbolic（ 符号的） but vital things like the German forest. Nature, in its current form in Germany, European nature, will no longer exist in this form with unchecked climate change. We need a swift, radical（基本的） exit from fossil（化石的） fuels in all sectors. Felix Eckhard has achieved something historic together with environmental organizations and other individuals.

  Though the obligation to protect the environment is enshrined in the German constitution（章程）, it had led to little action. The decision is also getting a lot of attention from legal experts. Up to now, only people directly affected by climate change had a chance of bringing their case to court.