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Antarctica's ice sheets will continue to melt long after this century. Antarctica image from www.shutterstock.com

The Paris climate agreement set a “safe” global warming limit of below 2℃, aiming below 1.5℃ by 2100. The world has already warmed about a degree since the Industrial Revolution, and on our current emissions trajectory we will likely breach these limits within decades.

However, we could still come back from the brink with a massive effort.

But let’s take a closer look at that warming limit. If we accept that 1.5-2℃ of warming marks the danger threshold, then this is true whether it applies tomorrow, in 2100, or some time thereafter. What we need is to stay below these limits for all time.

Put it this way: we wouldn’t be satisfied if the brakes on a new car only worked on the day of purchase, or for two weeks after that – we expect them to keep us safe throughout the car’s lifetime.

The trouble is, limiting warming to well below 2℃ forever is a much harder job.

Millennia matter

Whatever warming we manage to prevent this century, the world will continue to respond to climate change after 2100.

Looking beyond 2100 is often considered irrelevant, given that electoral timescales only operate over several years, and individual development projects over several decades.

However, it is highly relevant to major infrastructure developments, such as overall city planning. Throughout Europe and Asia, the foundations of most city infrastructure date back centuries, or even millennia. Not incidentally, so do most of the supporting agricultural and fisheries traditions and transport routes.

Even the more recent developments in the Americas, Africa and Australia have fundamental roots that date back hundreds of years. Clearly, we need to think beyond the current century when we think about climate change and its impact on civilisation.

The short and the long of it

The climate system is made up of many different components. Some of these respond rapidly to changes, others over much longer timescales.

The components that respond rapidly to the impacts of greenhouse gas emissions include changes in cloud, snow and sea-ice cover, in dust content of the atmosphere, land-surface changes, and so on. Some work almost instantaneously, others over decades. Together these are known as the “transient” response.

Slow-responding components in the climate system include ocean warming, continental ice-sheets and exchanges of carbon between lifeforms, oceans, the sea floor, soils and the atmosphere. These work over many centuries and are known as the “equilibrium” response.

Large amounts of energy are needed to warm up such a large volume of water as the global ocean. The ocean has taken up more than 90% of all the extra heat caused by greenhouse gases emitted since the Industrial Revolution, especially into the upper few hundred metres.

However, the ocean is so vast that it will continue to warm from the top down over many centuries to millennia, until its energy uptake has adjusted to Earth’s new energy balance. This will continue even if no further emissions are made.

Ice sheets on Antarctica and Greenland respond to climate change like an accelerating heavy freight train: slow to start, and virtually unstoppable once they get going. Climate change has been building up since the onset of the Industrial Revolution, but only in recent decades have we started to see marked mass-loss increases from the ice sheets.

The ice-sheet freight train has at last come up to speed and now it will keep on rolling and rolling, regardless of what immediate actions we take regarding our emissions.

Looking to the past

Carbon dioxide levels have reached 400 parts per million (ppm). To find out what this means for the coming centuries, we have to look between 3 million and 3.5 million years into the past.

Temperature reconstructions suggest the world was 2-3℃ warmer than before the Industrial Revolution, which is similar to the expected equilibrium response for the future.

Geological data from the last 65 million years indicate that the climate warms 3-5℃ for every doubling of CO₂ levels.

Before the Industrial Revolution, CO₂ levels were around 280 ppm. Under all but the most optimistic emission scenarios of the Intergovernmental Panel on Climate Change (IPCC), the first doubling (to 560 ppm) is approached or crossed between the years 2040 and 2070.

While we don’t know exactly how high sea level was 3.5 million years ago, we are confident that it stood at least 10 metres higher than today. Most studies suggest sea-level rise around 1m higher than today by 2100, followed by a relentlessly continued rise by some 2m per century. Even a rise of a metre or more by 2100 is murderously high for global infrastructure, especially in developing countries.

Today, some 600 million people live at elevations within 10m of sea level. The same area generates 10% of the world’s total GDP. It is estimated that a sea-level rise of 2m will displace almost 2.5% of the global population.

Even the more immediate impacts of sea-level rise are enormous. In 136 of the world’s largest port cities, the population exposed to flooding is estimated to increase by more than three times by 2070, due to combined actions of sea-level rise, land subsidence, population growth and urbanisation. The same study estimates a tenfold increase in asset exposure.

Back to the future

The eventual equilibrium (long-term) level of warming is up to twice the transient (short-term) level of warming. In other words, the Paris Agreement’s response of 1.5-2℃ by 2100 will grow over subsequent centuries toward an equilibrium warming of 2.3-4℃, even without any further emissions.

Given that we have already reached 1℃ of warming, if the aim is to avoid dangerous warming beyond 2℃ over the long term, we have to avoid any further warming from now on.

We can’t do this by simply stopping all emissions. This is because there is still some warming to catch up from the slower transient processes. To stop any further warming, we will have to reduce atmospheric CO₂ levels to about 350 ppm. Doing so requires both stopping the almost 3ppm rise per year from new emissions, and implementing carbon capture to pull CO₂ out of the atmosphere.

Global warming would be limited to 1-1.5℃ by 2100, and 2℃ over the long term, and in addition ocean acidification would be kept under control. These are essential for containing the impacts of climate change on global ecosystems.

This is the real urgency of climate change. Fully understanding the challenge can help us get to work.

Eelco Rohling receives funding from the Australian Research Council (ARC) and the UK Natural Environment Research Council (NERC). He is Professor of Ocean and Climate Change at The Australian National University (ANU) and the University of Southampton (UK), and a member of ANU's Climate Change Institute (CCI).

Barack Obama visits Baton Rouge on Tuesday, telling residents affected by historic flooding that the country will continue to support them and help them rebuild their lives. Obama also takes a dig at Donald Trump, saying ‘this is not a photo op issue’ . The floods have killed at least 13 people and damaged tens of thousands of homes

• Obama digs Trump in flood-damaged Louisiana: ‘not a photo-op’ – politics live

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Tourists gather in Transylvania to help with the traditional mountain hay harvest. BBC Gaelic Journalist Teàrlach Quinnell went with them.

In honor of the National Park Service’s centennial this week, the Guardian has compiled scenes from around the country. President Woodrow Wilson signed the act creating the National Park Service 100 years ago. From coast to coast, Hawaii to Maine, the beauty, nature and scope of US national parks are breathtaking

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Most countries in the world have little capacity to deal effectively with invasive species, a study suggests.

Hailed as ‘America’s best idea’, the parks are hugely popular with the public but face political efforts to lift federal protection and allow private development

“It’s easy to feel besieged here,” said Wendy Ross, superintendent of the Theodore Roosevelt national park. Ross’s park, named after the “conservationist president” who helped to keep America’s natural treasures unspoiled, is surrounded by oil and gas drilling that has transformed the landscape.

Related: 100 years of America’s national parks – in pictures

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Corruption in many Pacific countries appears endemic, the Pacific has the world’s fastest growth rate of HIV infection and the Pacific is predicted to surpass Africa as the world’s poorest region in the foreseeable future Is the Pacific not sinking but being sunk?

Corruption in many Pacific countries appears endemic, the Pacific has the world’s fastest growth rate of HIV infection and the Pacific is predicted to surpass Africa as the world’s poorest region in the foreseeable future Is the Pacific not sinking but being sunk?

As part of a new series on elephant conservation we’d like to hear about your experiences with the world’s largest land mammal

Over the next year we’re going to be covering the plight of elephants around the world. The numbers of these beautiful animals – now our largest land mammal – have been in steep decline for a century and now face more serious challenges than ever, due to poaching, habitat destruction, and conflict with man.

Please help with our coverage by getting in touch and telling us your own stories, encounters and campaigns. Are you a wildlife campaigner in Asia? A grassroots activist in Africa? Whoever you are, we want to hear from you about your own encounters with elephants.

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Demonstrators focus on driving up policing costs as anti-bovine TB programme expanded across south-west England

Protesters against the badger cull in England have said they plan to change tactics by undertaking direct action to drive up policing costs, following reports of an expansion of culling to new areas.

The BBC has reported that the cull will be extended to five new areas in south-west England – south Devon, north Devon, north Cornwall, west Dorset and south Herefordshire – where badger shooting will begin in early September as part of government efforts to eradicate bovine TB.

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Activists and scientists around the world agree with Sheila Watt-Cloutier: 'You save the Arctic, you save the planet'.

Climate Institute report says negative-emissions technology is imperative because risks of global temperature reaching 2C are ‘unmanageable’

Australia will blow its carbon budget with either the Coalition’s emissions reduction targets, or those suggested by the Labor opposition, highlighting the urgent need for negative-emissions technology, analysis commissioned by the Climate Institute shows.

“Everyone is just now beginning to work out the implications of the 1.5C goal, and how hard it is to get to it,” said John Connor, chief executive of the Climate Institute.

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Conservation group says it is committed to upholding Australian federal court ruling banning the slaughter of whales in the Australian sanctuary

A United States court ruling preventing conservationists from attacking Japanese whaling boats will not stop the annual protection campaign in the Southern Ocean.

The Japanese Times newspaper reported on Tuesday that a settlement declaring the Sea Shepherd Conservation Society was “permanently enjoined from physically attacking the [Japanese] research vessels and crew and from navigating in a manner that is likely to endanger their safe navigation”.

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Energy Gardens is a pan-London community garden project where reclaimed land alongside overground train stations and track is cultivated by local community groups. Up to 50 gardens will be created across the rail network.

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The August 2016 issue of the Commonwealth environmental water latest facts is now available.

Unforgiving temperatures of up to 60C (140F) beat down on these saltminers on a daily basis. The mines, situated in the Afar Triangle in Ethiopia, stretch across 38,000 sq miles and at their lowest point are more than 300ft below sea level. Joel Santos travelled to capture the area’s dry, brutal beauty

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There has been a massive spike in the amount of recycling that gets rejected.

Light pollution conceals true darkness from 80% of Europe and North America. What do we lose when we can no longer see the stars?

Every civilisation we know of has devised a system – scientific, religious, what have you – to make sense of the night sky. The mystery of what’s up there, where it came from, and what it means has been inherited and puzzled over for generations. Those questions may be the most human ones we have.

Due to pervasive light pollution – glare from excessive, misaimed and unshielded night lighting – 80% of Europe and North America no longer experiences real darkness. For anyone living near a major metropolis, a satellite image of the Milky Way seems abstract: we understand it to be a document of something true, but our understanding is purely theoretical. In 1994, after a predawn earthquake cut power to most of Los Angeles, the Griffith Observatory received phone calls from spooked residents asking about “the strange sky”. What those callers were seeing were stars.

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Australia's treeless alps are vulnerable to the spread of woody shrubs. Alps image from www.shutterstock.com

Australia’s ecosystems are already showing the signs of climate change, from the recent death of mangrove forests in northern Australia, to the decline in birds in eastern Australia, to the inability of mountain ash forests to recover from frequent fires. The frequency and size of these changes will only continue to increase in the next few years.

This poses a major challenge for our national parks and reserves. For the past 200 years the emphasis in reserves has been on protection.

But protection is impossible when the environment is massively changing. Adaptation then becomes more important. If we are to help wildlife and ecosystems survive in the future, we’ll have to rethink our parks and reserves.

A weedier world

Climate change is predicted to have a substantial effect on our plants and animals, changing the distribution and population of species. Some areas will become unfavourable to their current inhabitants, allowing other, often weedy, species to expand. There will likely be widespread losses in some ecosystems as extreme climate events take their toll, either directly by killing plants and animals, or indirectly by changing fire regimes.

While we can model some of these changes, we don’t know exactly how ecosystems will respond to climate change.

Australia has an extensive natural reserve system, and models suggest that much of this system is expected to be altered radically in the next few decades, resulting in the formation of totally new ecosystems and/or shifts in ecosystems.

Yet with rapid climate change, it is likely that ecosystems will fail to keep up. Seeds are the only way for plants to move, and seeds can only travel so far. The distribution of plants might only shift by a few metres a year, whereas the velocity of climate change is expected to be much faster.

As a result, our ecosystems are likely to become dominated by a low diversity of native and exotic invasive species. These weedy species can spread long distances and take advantage of vacant spaces. Yet the exact nature of changes is unknown, particularly where evolutionary changes and physiological adaptation will assist some species but fail others.

Conservation managers are concerned because with increasing weediness will come a loss of biodiversity as well as declines in the overall health of ecosystems. Plant cover will decrease, triggering erosion in catchments that provide our water reservoirs. Rare animal species will be lost because a loss of plant cover makes them more susceptible to predators. A cascade of changes is likely.

From conservation to adaptation

While climate change threats are acknowledged in reports, we continue to focus on conserving the state of our natural environments, devoting scarce resources to keeping out weedy species, viewing vegetation communities as static, and using offsets to protect these static communities.

One way of preparing for the future is to start the process of deliberately moving species (and their genes) around the landscape in a careful and contained manner, accepting that rapid climate change will prevent this process from occurring quickly enough without some intervention.

Overseas plots covering several hectares have already been established that aim to achieve this at a large scale. For instance, in western North America there is a plot network that covers 48 sites and focuses on 15 tree species planted across a three-year period that covers temperature variation of 3-4°C.

In Australia, a small section of our reserve system, preferably areas that have already been damaged and/or disturbed, could be set aside for such an approach. As long as these plots are set up at a sufficiently large scale, they can act as nursery stock for the future. As fire frequency increases and exceeds some plants' survival capabilities, the surviving genes and species in these plots would then serve as sources for future generations. This approach is particularly important for species that set seed rarely.

Our best guesses about what will flourish in an area in the future will be wrong in some cases, right in others, but ongoing evolution by natural selection in the plots will help to sort out what really can survive at a particular location and contribute to biodiversity. With a network of plots established across a range of natural communities, our protected areas will become more adaptable for a future where many species and communities (along with the benefits they provide) could otherwise be lost entirely.

As in the case of North America, it would be good to see plots set up along environmental gradients. These might include from wet to dry heading inland, and from cold to warm heading north-south or with changing altitude.

One place to start might be the Australian Alps. We could set aside an area at higher altitude and plant low-altitude grasses and herbs. These may help current plants compete against woody shrubs that are expected to move towards our mountain summits.

Lower down, we might plant more fire-tolerant species in mountain ash forests. Near the coast, we might plant species from further inland that are better at handling drier conditions.

The overall plot network should be seen as part of our national research infrastructure for biodiversity management. In this way, we can build a valuable resource for the future that can serve the general community and complement our current ecosystem monitoring efforts.

Ary Hoffmann receives funding from the Terrestrial Ecosystem Research Network and the Australian Research Council. He is a member of the IUCN Climate Change Specialist Group.

A subculture of Tesla Model S drivers is discovering the joys, and tribulations, of converting their $US145,000 Model S into a very fancy tent.