WE ARE BORN; we live; at some point, we die. The notion that our existence is limited by time is fundamental to human experience. We can’t fight it – and truth be told, we don’t know what we are fighting against. Time is a universal whose nature we all – and physicists especially – fail to grasp. But why is time so problematic? “If we had a really good answer to that question,” says , a theoretical physicist at the University of Southern Denmark in Odense, “then it wouldn’t be so problematic.”

On a certain level, time is simple: it is what stops everything happening at once. That might seem flippant, but it is at least something people can agree on. “The causal order of things is really what time is all about,” says Eichhorn.

Viewed this way, the existence of time can be interpreted as a necessary precondition for the sort of universe where things lead to other things, among them intelligent life that can ask questions, such as “what is time?”. Beyond that, time’s essence is mysterious. For instance, why can things only influence other things in one direction in time, but in multiple directions in the three dimensions of space.

Most physical theories, from Isaac Newton’s laws of motion to quantum mechanics, skirt such questions. In these theories, time is an “independent variable” against which other things change, but which can’t be changed by anything else. In that sense, time exists outside physics, like the beat of a metronome outside the universe to which everything inside it plays out.

Albert Einstein’s theories of relativity, developed in the early 20th century, threw such ethereal notions over a barrel. In relativity, time is a physical, dynamic thing, fused with space to form space-time – the fabric of the universe itself. And space-time isn’t absolute, but relative, warped by motion and gravity. If you travel fast, or if you are in a strong gravitational field, it slows down.

The relativity of time has wide-ranging consequences. Because there is no unique way of defining its passage, there is no unique way of defining “now”. Einstein concluded that all “nows” – past, present and future – must exist simultaneously, a picture known as the block universe that is completely at odds with our intuitions.

That mismatch occurs because, in our universe, the speed of light is finite. We can only reach certain times within a certain, well, time, so we can never achieve that God-like block-universe view. “In practice, causality limits what we can perceive in a very strict way, and our experience and anything that affects us is limited strongly by causality,” says cosmologist .

Time and space

The mysteries don’t stop there. By making time part of the physical fabric of a universe that, as far as we can tell, began in a big bang some 13.8 billion years ago, Einstein’s theory of general relativity implies that time itself had a beginning – and perhaps an end, too. There can be no eternal metronome ticking outside the universe as quantum theory implies, because such a source would have to exist outside space and time itself. This sets up a currently unbridgeable divide between relativity and quantum theory. In attempting to cross it, researchers such as Eichhorn hope to make progress towards a more unified picture of physics – one that would have to have a very different conception of time.

Many “quantum gravity” theories propose that if you could zoom in very close to the fabric of Einstein’s space-time, to a fine-grained level known as the Planck scale, you would discover a substructure – a kind of quantum pixelation. That would open up entirely new possibilities. “It may very well be that the quantum structure of space and time is different in the presence of matter than it is if you’re just thinking of sort of a universe which contains just space and time,” says Eichhorn.

Not everyone thinks we need to go that far. Some see an avenue to finding the nature of time in a better understanding of quantum theory. Or perhaps time is itself a mirage. Like the colour or pattern of a tree leaf, time might be something of no significance, says Mack, the passage of which we invent to make sense of local patterns around us and our own lives.

After all, we never measure time itself, but rather regular changes – be it the passage of the seasons, the swing of a pendulum or the oscillation of a caesium atom – that we reverse-engineer into some mysterious thing we call “time”. “It’s something that we see, and that appears to be there,” says Mack. “It may not matter to the cosmos.”

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Here we are at the end of the line – sort of. Today is notionally the last day of the COP26 climate summit, but it now seems almost inevitable that the talks will run into extra time. So while this is the final daily update, the conclusions are necessarily provisional. We’ll have more, conclusive analysis next week when the summit is really, truly over.

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It’s the final countdown – blah-blah-blah blah?

We don’t yet know what the final decision texts from COP26 will say, but we do have the latest drafts. Expected last night, they were actually released a little after 7am GMT, after another overnight session. Hopefully the negotiators had plenty of caffeine. It does remind me of Jim Hacker on the BBC programme Yes, Prime Minister mentioningĚý“”.

Anyway, the have prompted a lot of discussion, focused largely on whether they are stronger or weaker than the originals. There are a few key changes.

The original draft referred to phasing out coal. This has been softened to “unabated coal”, meaning coal-fired power plants that don’t have a carbon capture and storage (CCS) system to trap their greenhouse gas emissions and bury them underground. Your mileage may vary on this, depending on your faith in the usefulness of CCS. The technology would allow some fossil fuels to be burned without impacting the climate. It does seem to work, but it needs a lot of infrastructure and is consequently expensive. Most scenarios for limiting warming to 1.5°C do use some CCS, but there is a strong case that it ought to be reserved for processes like steel manufacturing that are inherently difficult to decarbonise, rather than to keep dirty coal-fired power stations running. At any rate, it seems clear that a world without unabated coal will be better than one with it, so this bit of the text does represent progress.

Perhaps more seriously, a push to get rid of subsidies for fossil fuels has been : it now refers only to “inefficient” subsidies. What this means is beyond me. If we want to rapidly reduce and eventually halt the use of fossil fuels, governments ought not to subsidise their use in any way. There is no such thing as an efficient fossil fuel subsidy. So this change seems like an unambiguous weakening of the text.

Events surrounding the summit have only reinforced the sense that the fossil fuel industry still has too much influence on governments. Campaign group Friends of the Earth for opting to back 30 major gas projects to the tune of €13 billion. In the UK, the Mirror newspaper revealed that .

On the positive side, one of the most crucial bits of the COP26 text seems to have survived. This is the push for countries to . The language has changed: the text now “requests” countries to do this, where previously it saidĚý “urges”. . If this sort of linguistic tomfoolery makes your head hurt, just ignore it. , the key thing is that the instruction to come up with new plans by the end of 2022 has come through the most recent round of edits, and may well make it to the final text.

Another key area where the text has improved is finance. Higher-income countries have agreed to double the money they give to help lower-income countries adapt to climate change, by 2025. They currently give about $20 billion per year. There is also the related question of the higher-income countries’ promise to deliver $100 billion a year of climate finance to lower-income nations by 2020. This promise wasn’t kept, and in the latest draft the higher-income countries have agreed to express “deep regret” for this. The text now “urges” them to meet the annual target by 2025.

Finally, there is loss and damage: the notion that people who have been harmed by climate change, and who cannot adapt, ought to be compensated for the losses they experience. We are a long way from any money actually changing hands, but COP26 saw some movement. The draft text includes a decision to create a “technical assistance facility”, and . These are baby steps.

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A tentative ending

Bearing in mind that this is all still provisional, how might we sum it up? The first thing to say is that, overall, a lot of the bigger statements have survived and there are some new ones. It isn’t a nothingburger. There are still , but some have been closed and others are closing. żěè¶ĚĘÓƵ’s Richard Webb puts it like this: “Weaker on mitigation [cutting emissions] than we would have wanted, stronger on adaptation than we would have thought.”

Since it’s my last day writing these newsletters, I’ll offer my own take, predicated on the final text being largely the same as the current drafts. My feeling is that COP26 would have been universally viewed as a highly successful climate summit if it had been held in 2001 or 2011, rather than in 2021. Why would I say that? After all, the international plan that is emerging is obviously inadequate to the situation at hand, putting us on course for 2.4°C of warming instead of 1.5°C. However, the fact we aren’t on course for 1.5°C is more a reflection of the failure of so many of the previous 25 COPs. Before COP26, we were on course for 2.7°C of warming: now we are looking at 2.4°C. That is a real, significant improvement. It’s just that most of the other summits didn’t achieve anything like as much.

Unless you actually believe that a single one of these summits ought to be enough to get all the world’s countries to agree to a wholesale transformation of their infrastructures and economies, there is no way that the problem could ever be solved outright by COP26 – or COP25, COP24 or any of the others. The actual progress made here has been pretty solid, knocking 0.3°C off the expected warming. There are also the more unquantifiable symbolic shifts, like the text actually calling out fossil fuels by name. These don’t directly translate to emissions cuts but may give political leaders some impetus. If all of the previous COPs had made as much progress as COP26, we would have this climate change problem sorted by now.

Some of you will nevertheless be feeling pretty upset at the outcome. You may be , frustrated or enraged. I feel pretty much all of those emotions. The answer is to get angry. There have been global protests about climate change over the past few years, and it seems likely that they provided at least some of the fuel for the progress that has been made. If COP26 infuriated you, tell your representative. Go join a protest. The more we demand action, the more action our leaders will take. . Book your train tickets now and go make some .

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What to watch for

This is the last of żěè¶ĚĘÓƵ’s daily updates from COP26, but it isn’t the end of our coverage. Look out for more stories on the website as the summit winds to a close, and a final analysis from chief reporter Adam Vaughan next week.

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Quote of the Day

“I’m actually here to beg you to prove us wrong.” Climate activist spoke for many young people when that she simply didn’t believe the promises they were making, nor did she believe that they were sincere about wanting to help.

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Sign up for Today at COP26, our free daily briefing on all the latest news and analysis from the crucial climate summit

Just before 6am UK time, the first draft of the COP26 final statement was released. It was expected to come out around midnight, but instead, the negotiators had to work through the night. The text gives us our first concrete notion of what the world’s governments will agree to this week. Of course, it is still a draft, and the final version may look significantly different. But let’s take a look at what we have.

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Fossil fuels! It’s the fossil fuels! OMG!

żěè¶ĚĘÓƵ’s Adam Vaughan and has summarised what is in the text. He highlights several key points.

First, “calls upon Parties to accelerate the phasing-out of coal and subsidies for fossil fuels”. That’s remarkable for one simple reason: it explicitly mentions fossil fuels. at the European Climate Foundation in the Netherlands that analysts reckon this is the “first time fossil fuels have been called out in a draft UN #climate decision text” – – and called it “a moment”.

“We’ve never had a text like that before in the COP, a reference specifically to phasing out fossil fuel subsidies or to phasing out coal,” at the World Resources Institute, .

To readers out there in the normal world, this may seem utterly bizarre. Climate change is driven in large part by our use of fossil fuels and the greenhouse gases they release. Obviously. And yet in the topsy-turvy world of international diplomacy, many countries have simply refused to formally commit to this basic fact. It would be possible to write quite a long book exploring the psychological, economic and political reasons for that – but the fact is they haven’t said it before. If this line makes it into the final document, for the first time all the world’s governments will have admitted that fossil fuels are the problem.

The symbolic value of this one line is potentially quite significant. But of course, symbolic acts only matter if they prompt people to do meaningful things – otherwise they don’t amount to anything more than “”. Is there anything practical in there?

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Revisiting pledges

Probably the most useful bit of the text concerns emissions pledges. Many countries have made commitments to cut their greenhouse gas emissions by so many percentage points by some future date. The text calls on them to “revisit and strengthen” their 2030 climate plans . Previously, they weren’t expected to put forward new plans until 2025, so these new plans would come a whole three years early – and would relate to emissions this decade rather than after 2030.

That’s complicated, so let’s boil it down. This bit of text pushes countries to make plans, before the end of next year, to cut emissions this decade. That’s crucial, because as we have noted before, while many countries have committed themselves to hit net-zero emissions this century, in most cases they haven’t followed up with plans for emissions cuts this decade. If governments put forward , for action before 2030, it would help fill that crucial gap.

Of course, the big issue here is that the text only “urges” governments to do this. It doesn’t compel them. So even if this text survives the next few days of negotiations, it won’t be in any way legally binding. We will have to rely on governments feeling a sense of obligation, or perhaps shame, for the text to matter.

Given all this hedging, it will come as no surprise that many are disappointed. Rupert Read, a former spokesperson for eco-activism group Extinction Rebellion, called the text “”. Similarly, Jennifer Morgan at Greenpeace said it was “”.

Meanwhile, a group of 14 teenagers, disillusioned with the COP26 process, have launched calling on the United Nations to declare a “system-wide climate emergency”. , the group includes Greta Thunberg plus Ranton Anjain and Litokne Kabua from the Marshall Islands, Ridhima Pandey from India, Alexandria Villaseñor from the US and Ayakha Melithafa from South Africa. Their hope is that such a declaration would prompt the UN to send resources to countries vulnerable to climate change.

It is understandable that the teenagers are so utterly done with the international negotiations and are trying to do an end run around them. In 2021, after 26 of these climate change summits, the language of the draft agreement is still wishy-washy.

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Clean cars

In other news, cars powered by fossil fuels are on the way out – sort of.Ěý

The UK government today that “all new heavy goods vehicles in the UK will be zero-emission by 2040”. Because the government has already made similar commitments about other classes of vehicle, this means that all new road vehicles in the UK will have to be zero emission by 2040.

On a larger scale, a coalition of 24 countries and several leading car firms have agreed to end the sale of new fossil fuel cars by 2040.

The list of countries includes Canada, Israel and the UK – but doesn’t include several nations with massive car industries, . There are also long lists of cities, fleet owners and investors that have signed on. The car manufacturers involved include Mercedes-Benz, Ford and General Motors. But again, there are many key absences, notably BMW, Volkswagen and Toyota.

Still, the coalition is substantial as it is, and may well grow. What is more worrying is the woolliness of the language. For instance, the governments commit to “work towards all sales of new cars and vans being zero emission by 2040 or earlier, or by no later than 2035 in leading markets”. Notice the use of “work towards”, as opposed to “ensure”. Also, if you scroll to the very bottom of , you will find a teeny-tiny footnote that reads: “We will make clear this declaration is not legally binding and focused on a global level”. To which one can only say “oh”.

Nevertheless, at the UN Environment Programme, told żěè¶ĚĘÓƵ’s Richard Webb that, despite these caveats, this represents a real turning point. “It’s a fantastic development, it’s an impressive list,” he says, adding that he thinks more will sign up soon.

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What to watch for

Climate finance: that is, money flowing from developed countries to developing and emerging economies to help them both cut emissions and adapt to the impacts of climate change. COP26 president Alok Sharma has pronounced himself “” with the commitments made so far, noting that contributions to the Least Developed Countries Fund have topped $410 million and contributions to the Adaptation Fund have reached over $350 million. Once again, a reminder that all the way back in 2009, rich countries promised $100 billion a year by 2020 and . In 2019, . Sharma has a long way to go to get the finance flowing as it is supposed to.

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Quote of the day

“.” Teenage climate activist Alexandria Villaseñor of , once again on point. As this edition of the newsletter makes clear, the texts produced by international climate summits often fail to admit even basic facts – and governments have broken many of the promises they have made to each other.