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Negotiating the realities of a changing climate and its impact on horticultural crops.

Queensland court of appeal finds ‘proposed mining would not detrimentally affect global greenhouse gas emissions’ because Asian power stations would buy coal elsewhere if Alpha blocked

Miners could run afoul of Queensland’s environmental protection laws if the burning of their export coal overseas were shown to negatively impact global carbon pollution, the state’s highest court has ruled.

But the court of appeal has dismissed a challenge to Gina Rinehart’s Alpha mine because of an earlier land court finding that it would “not detrimentally affect global greenhouse gas emissions” because Asian power stations would simply buy coal elsewhere if the mine were blocked.

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World’s biggest solar module supplier JinkoSolar says Australian solar market set for rebound as households adopt battery storage, and large scale sector takes off.

Former prime minister says commercial shark fishery should be considered for north coast of New South Wales

Tony Abbott has called for nets to be put in place to protect beachgoers in regional New South Wales, saying he is on the side of people rather than sharks, after a teenager was bitten while surfing.

The former prime minister has argued that it was unfair nets were in place off metropolitan beaches but not regional ones.

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Reports in the local Chinese media suggest that a record-low bid of 0.52 yuan/kWh for solar has been accepted in Inner Mongolia.

72% of Australians believe it is inevitable the country’s current coal-fired power stations will be closed and replaced with renewable energy. The real question is, how should we manage this transition?

Current greenhouse gas concentrations could warm the world 3-7℃ (and on average 5℃) over coming millennia.

China installed a wind turbine every hour and filled a football field full of solar panels every hour last year.

While we don’t know whether Hazelwood will close yet, we do know that Australia could easily replace the energy, and it could make a substantial difference to our carbon emissions.

Tiny plastic particles released by synthetic fabrics can cause harm to marine life when they enter rivers and oceans

Each cycle of a washing machine could release more than 700,000 microscopic plastic fibres into the environment, according to a study.

Related: Inside the lonely fight against the biggest environmental problem you've never heard of

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STAR WARS SCIENCE: Australian scientists have created their own version of a Star Wars scene by stopping light in a cloud of very cold atoms, a development that provides a essential building block for quantum computing.

Committee on Climate Change chair urges UK to bring in new laws to replace EU legislation and says Scotland must do more to prepare for global warming

The UK must not water down its environmental laws as it leaves the European Union, one of the government’s most senior advisers on climate change has warned.

Lord Krebs, chairman of the Committee on Climate Change (CCC), told the Guardian: “It will be absolutely crucial that governments in the UK replace European legislation and don’t see this as an opportunity to say we can now have dirtier vehicles or less efficient household appliances.”

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Two million years of climate records stored in ocean sediment cores point to three to seven degrees Celsius long term temperature rise at current levels of atmospheric carbon.

Nasa says jets of water spotted spurting from Jupiter's moon, Europa, take them a step closer to finding out if there is life in space.

The world's biggest conference on the international wildlife trade has begun in Johannesburg with the plight of Africa's elephants, targeted for their tusks, at the centre of heated talks.

Native bees are just some of the wildlife found in your backyard. MirandaKate/Flickr, CC BY-NC

As the weather warms and days lengthen, your attention may be turning to that forgotten patch of your backyard. This week we’ve asked our experts to share the science behind gardening. So grab a trowel and your green thumbs, and dig in.

Whether you live in an urban apartment or a rural homestead, your outdoor area is more than just a private space. Ecologically, a garden is another jigsaw piece in the landscape.

Whatever their size, gardens can contribute to natural functions and processes in the local area, such as regulating water drainage, buffering the damaging effects of strong winds, or providing food and shelter for native wildlife.

Many wildlife species survive in urban areas, but their presence and persistence depend on how specific their food and shelter needs are, how they respond to disturbances, and the quality and quantity of other green spaces in the landscape.

For larger animals, such as birds and mammals, a home garden could become a stepping stone across an otherwise hostile urban landscape. For smaller animals, such as insects, it could be the centre of their home range.

In urban areas, where space is often limited, gardening with pollinators in mind is a simple way to encourage biodiversity in the backyard. And, depending on the surrounding landscape, habitat for pollinators will also be habitat for other animals.

Butterflies are important pollinators in backyards. John Tann/Flickr, CC BY Flowers are just the first step

Flowers produce sugar (nectar) and protein (pollen), the main diet for many adult insects and birds. Unlike other insect groups, native bee larvae develop almost exclusively on pollen collected by their parents, so flowers are essential to grow native bee populations.

There is no single best combination of flowers for wild bees. Many “plants for pollinators” lists available online are based on local experiences and rarely apply to all geographic regions. A general rule of thumb for a pollinator garden is one that produces flowers for most of the year and is built on diversity – monocultures of any single flower type or colour will suit only a very small number of generalist species.

Native plants are an ideal option for attracting native pollinator insects and birds, but many garden exotics, especially herbs, fruit and vegetable plants, are just as popular. Modern hybrid varieties should be chosen carefully, as some are bred for commercial fruit or flower traits (like size or colour), but the flowers lack the nectar or scent cues that attract pollinators looking for food.

Native plants can attract birds, such as this New Holland honeyeater. Cazz/Flickr Build it and they will come

The structure and design of a garden can determine what wildlife species will visit or make a home. Vertical structure, built from multiple layers of different plant heights, provides more spaces for wildlife to co-exist. Small plants and shrubs provide good shelter for insects and very small birds, while larger trees will attract visits from more mobile birds and mammals.

Large trees with rough or shedding bark that creates lots of cracks and crevices are excellent shelter for insects and small lizards. Trees that produce resins and sap flows, such as conifers, acacias and eucalypts, are also useful for some native bee and wasp species that use resin to seal their nest cells.

Insect hotels can provide homes for insects that usually nest in dead wood. But only a small proportion of the world’s bee species are wood-nesters. About 75% of bee species dig their nests into the ground, usually in sandy, uncompacted soil, preferably on a slope that won’t get waterlogged.

Insect hotels attract wood-nesting insects. Insect hotel image from www.shutterstock.com

It can be difficult to build all of this into small gardens, but many pollinator insects will have home ranges of a few hundred metres, while birds and mammals can travel much further. So landscape composition can also influence the wildlife potential of an individual garden. A high proportion of paved areas can reduce the number of wild bees or native birds in the neighbourhood. Highly manicured green spaces can also have a negative effect on wild bee species.

Disrupting the food chain

Like any ecosystem, gardens involve an intricate web of life, from the soil microbes underground to the birds in the trees. It’s easy to grab the spray bottle to kill off the dandelions and blow down the flies, but what are the knock-on effects?

Many of the animals and plants we think of as a backyard nuisance often provide services we don’t see. For example, many native wasp and fly species (even blowflies!) are pollinators as adults. And as larvae, they control many of the insect pests we see on our plants, or decompose organic wastes. Small reptiles, like geckoes and skinks, mostly feed on small insects that annoy us, like mosquitoes and midges.

Plants we think of as lawn weeds, particularly dandelions and clover, are a favourite food source for native bees and hoverflies. Aphids and scale insects also produce a sugary substance called honeydew as they suck on plants, which is an important sugar source for some beneficial insects like wasps, bees, ants and hoverflies.

Aphids produce sugars which are an important food source for other insects. ron_n_beths pics/Flickr, CC BY-NC

Limiting synthetic chemical use is one of the easiest and cheapest ways to enhance wildlife in gardens. Insecticides can kill beneficial insects, or affect them indirectly by disrupting their metabolism or reproductive cycles. Overuse of herbicides removes important food resources, like dandelions, that pollinators rely on if other flowers are scarce.

There is also the potential for chemicals to work in combination and have a greater impact.

Managing gardens as ecosystems

Many wildlife don’t like regular disturbances, which is why urban areas can be intimidating environments for animals. It can be hard to balance human needs with the habitat needs of wildlife. Many actions that minimise risks for humans can have the opposite effect for wildlife.

For example, pollinators generally prefer open grassy areas to dark forested areas. In urban environments, grassed areas are often mown regularly for human recreational and safety needs. This affects the availability of flowers for pollinators and also affects the persistence of these plant species. Mowing less often and outside peak flowering times can make a big difference for plants and pollinators.

Leaving a few weeds in the lawn can be a good thing for pollinators. tuchodi/Flickr, CC BY-SA

Similarly, large old trees are homes to myriad animals. Unless they pose a very real risk of danger to human lives, pruning overhanging branches can be better for the local ecosystem than removing the whole tree.

Wildlife are rarely deterred by fences, so it is likely that most of the animals you see in your yard are also using your neighbours’ yards. Managing gardens as a collective landscape, rather than individual gardens, can keep wildlife happy while also enhancing neighbourhood communication.

Manu Saunders is affiliated with the Institute for Land Water & Society and is co-founder of the Wild Pollinator Count.

NZ parrots | iPhone 7 | Pictures of autumn | Eating dirt | Bootle accents | Welsh signage

From your report (22 September) on the endangered New Zealand parrot the kea: “its destructive habits such as … attacking stock and habitually stealing food”. A wild creature has no concept of harm or property, so both “attacking” and “habitually stealing” are demonising anthropomorphism. The kea, like any other predator species, is simply and instinctively taking its share of nature’s bounty, the only way it could have survived until now. By any rational criterion, a wild animal is beyond human conceits of blame and responsibility.
Alex Watson
North Nibley, Gloucestershire

• Samuel Gibbs fingers a poor battery as the iPhone 7’s big weakness (Technology review, 24 September). This after five hours’ music, three hours’ browsing, photos, emails, etc. Allowing for seven hours sleep where do, you know, people, fit in?
Bill Steedman
Edinburgh

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Further evidence has been obtained to show that Jupiter's icy moon Europa throws jets of water out into space.

Party’s union donor says Britain would be forced to rely on ‘henchmen, hangmen and headchopper’ dictators for gas

Labour’s third biggest union donor has attacked the party’s decision to pledge a ban on fracking in the UK as “nonsense” and “madness”.

The GMB, which backed Owen Smith for the party leadership, criticised the move, saying it would force the UK to rely on foreign dictators – “henchman, hangmen and headchoppers” – for gas, as well as needlessly stop the creation of high-skilled jobs.

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Melting ice sheets – such as this one in Greenland – are one way the Earth amplifies global warming. Ice sheet image from www.shutterstock.com

Current greenhouse gas concentrations could warm the world 3-7℃ (and on average 5℃) over coming millennia. That’s the finding of a paper published in Nature today.

The research, by Carolyn Snyder, reconstructed temperatures over the past 2 million years. By investigating the link between carbon dioxide and temperature in the past, Snyder made new projections for the future.

The Paris climate agreement seeks to limit warming to a “safe” level of well below 2℃ and aim for 1.5℃ by 2100. The new research shows that even if we stop emissions now, we’ll likely surpass this threshold in the long term, with major consequences for the planet.

What is climate sensitivity?

How much the planet will warm depends on how temperature responds to greenhouse gas concentrations. This is known as “climate sensitivity”, which is defined as the warming that would eventually result (over centuries to thousands of years) from a doubling of CO₂ concentrations in the atmosphere.

The measure of climate sensitivity used by the Intergovernmental Panel on Climate Change (IPCC) estimates that a doubling of CO₂ will lead to 1.5-4.5℃ warming. A doubling of CO₂ levels from before the Industrial Revolution (280 parts per million) to 560ppm would likely surpass the stability threshold for the Antarctic ice sheet.

As the world warms, it triggers changes in other systems, which in turn cause the world to warm further. These are known as “amplifying feedbacks”. Some are fast, such as changes in water vapour, clouds, aerosols and sea ice.

Others are slower. Melting of the large ice sheets, changes in the distribution of forests, plants and ecosystems, and methane release from soils, tundra or ocean sediments may begin to come into play on time scales of centuries or less.

Other research has shown that during the mid-Pliocene epoch (about 4.5 million years ago) atmospheric CO₂ levels of about 365-415ppm were associated with temperatures about 3–4 °C warmer than before the Industrial Revolution. This suggests that the climate is more sensitive than we thought.

This is concerning because since the 18th century CO₂ levels have risen from around 280ppm to 402ppm in April this year. The levels are currently rising at around 3ppm each year, a rate unprecedented in 55 million years. This could lead to extreme warming over the coming millennia.

More sensitive than we thought

The new paper recalculates this sensitivity again – and unfortunately the results aren’t in our favour. The study suggests that stabilisation of today’s CO₂ levels would still result in 3-7℃ warming, whereas doubling of CO₂ will lead to 7-13℃ warming over millennia.

The research uses proxy measurements for temperature (such as oxygen isotopes and magnesium-calcium ratios from plankton) and for CO₂ levels, calculated for every 1,000 years back to 2 million years ago.

Some other major findings include:

The Earth cooled gradually to about 1.2 million years ago, followed by an increase in the size of ice sheets around 0.9 million years ago, and then followed by around 100,000-year-long glacial cycles.

Over the last 800,000 years, and particularly during glacial cycles, atmospheric greenhouse gas concentrations and global temperature were closely linked.

The study shows that for every 1℃ of global average warming, Antarctica warms by 1.6℃.

So what does all this mean for the future?

Global warming past and future, triggered initially by either changes in solar radiation or by greenhouse gas emissions, is driven mainly by amplifying feedbacks such as warming oceans, melting ice, drying vegetation in parts of the continents, fires and methane release.

Current CO₂ levels of around 400ppm, combined with methane (rising toward 1,900 parts per billion) and nitric oxide (around 310ppb), are already driving such feedbacks.

According to the new paper, such greenhouse gas levels are committing the Earth to extreme rises of temperature over thousands of years, with consequences consistent with the large mass extinctions.

The IPCC suggests warming will increase steadily as greenhouse gases increase. But the past shows there will likely be abrupt shifts, local reversals and tipping points.

Abrupt freezing events, known as “stadials”, follow peak temperatures in the historical record. These are thought to be related to the Mid-Atlantic Ocean Current. We’re already seeing marked cooling of ocean regions south of Greenland, which may herald collapse of the North Atlantic Current.

As yet we don’t know the details of how different parts of the Earth will respond to increasing greenhouse gases through both long-term warming and short-term regional or local reversals (stadials).

Unless humanity develops methods for drawing down atmospheric CO₂ on a scale required to cool the Earth to below 1.5°C above pre-industrial temperature, at the current rate of CO₂ increase of 3ppm per year we are entering dangerous uncharted climate territory.

Andrew Glikson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.