If week one of the climate conference in Glasgow set out a strong outline, the task for next week is to fill in as many details as possible. The long-term ambition of the global environmental policy now being negotiated would have been hard to imagine just a few years ago. While it is not yet clear exactly where the various pledges will get us to in terms of limiting temperature rises, the new agreement on methane spearheaded by President Joe Biden and a commitment by India to get half of its energy from renewable sources by 2030 are highly significant.Also encouraging is the more integrated approach to the many environmental challenges humanity faces. Previously, conservation and biodiversity were to some extent viewed as separate issues from the changing atmospheric chemistry that drives global heating. Now, with a promise to reverse deforestation and provide funding directly to indigenous people to help them protect their lands, there is greater recognition of the vital part that nature plays in regulating the climate.The pledges made so far are far from sufficient, and must be viewed as part of a continuing process. The decisions by China’s Xi Jinping and Russia’s Vladimir Putin to stay away inevitably undermine confidence in the overall project. Their refusal, along with India, to join the methane agreement is worrying. The possibility of a return to office by Donald Trump, or the election of a Republican in a similar mould, must be regarded as a serious threat. But there is a sense of momentum in Glasgow, and many climate scientists are relieved that the goal (a net zero planet) is increasingly accepted, even as arguments about how to get there continue to rage.Investment in new technologies such as “clean” aviation fuel should be encouraged, as subsidies for fossil fuels are cut off. The pace of development in the wind and solar industries has been astonishing. There are some grounds for optimism about the role that the private sector can play in the transition ahead. But nonexistent technology, and the hopes invested in it, played an oversized role in the UK government’s recently launched net zero strategy. One of the challenges of the coming days is to ensure that the plans put forward by governments, known as nationally determined contributions, are not built on wishful thinking. Years of delays mean that the timetable is incredibly tight. Leaders cannot afford to be passive.Once commitments have been made, mechanisms must be developed to measure and report on progress. This is an enormous task that will not be completed at the first attempt. With regard to the $100bn (£70bn) of climate finance that is supposed to be provided annually by rich countries to poorer ones, for example, more transparency is needed. Poor countries cannot be expected to choose green energy over fossil fuels unless they are supported. Calls from India and African countries for massively increased sums (Narendra Modi has suggested $1tn annually) make the establishment of a trusted carbon accounting system all the more urgent.After a dip during the pandemic, global emissions have jumped alarmingly. Unless they start to fall dramatically over the next two years, Cop26 will have been a failure. Overshadowing all the technical details is the overwhelming injustice of a situation in which the countries that have contributed least to global heating are already suffering most from its effects. This is a moral point, but also a practical and political one. Eliminating carbon emissions is a collective endeavour in which our civilisation must succeed if it is to continue to thrive. Questions of environmental justice, engaging the past as well as the future, must be confronted head-on in the days ahead.