Nerve gas is back. Images of the victims and reports from doctors on the scene of yesterday’s Syrian government air strike on the rebel-held northern town of Khan Sheikhoun suggest the weapon used was the nerve agent, sarin. At least 70 men, women and children died and hundreds were injured.

The timing of the attack seems startling, just a day ahead of today’s meeting in Brussels at which 70 countries are meant to discuss funding the reconstruction of Syria, and a week after previous US calls to remove Syrian president Bashar al-Assad. It may have been aimed at sowing discord among Western allies, or demonstrating the regime’s defiance.

But it could also just be a continuation of war as usual for the Assad regime, which has been increasingly using chemical attacks to terrorise civilians for the past several months, even though in 2013 it signed the international treaty banning chemical weapons and agreed to let its chemical stockpile be destroyed.

It is not yet certain what chemical was involved in the attack, cautions chemical weapons expert Jean-Pascal Zanders. But doctors from the (SAMS) who are in the area say victims exhibited “constricted (or ‘pinpoint’) pupils, foaming at the mouth, and the loss of consciousness, slow heart rate, slow breathing, vomiting, muscles spasms and other neurological symptoms consistent with nerve agents”.

“The symptoms described are consistent with exposure to sarin or some other organophosphorus chemical,” says Ralf Trapp, a consultant formerly with the Organisation for the Prohibition of Chemical Weapons (OPCW). “As some of the victims have been moved to Turkey, it may be possible to acquire biomedical samples from them to identify telltale chemical compounds formed by sarin reacting with molecules in the blood.”

Russia, the Syrian government’s main ally, claims the incident in Khan Sheikhoun for chemical weapons.

There are reasons to doubt this. For one thing, sarin is unstable, and the Assad regime chose to stockpile its precursor chemical, which would be mixed with another chemical just before use to produce sarin. Any rebel-made agent would probably be handled similarly. Hitting a cache of this would release little sarin.

Moreover, if Syrian air strikes released the agent by accidentally hitting an enemy cache, they were improbably lucky, as they managed to do the same thing at three separate locations in the area within 24 hours: SAMS reports two attacks on nearby villages the previous day that produced fewer casualties but with similar symptoms.

And a Syrian government also produced victims displaying symptoms of sarin. There was little international response, partly because “we cannot confirm the chemical used unless inspectors can take samples under proper conditions”, says Zanders.

Access

Assad seems unlikely to allow such access again. In 2013 the Syrian government launched a major attack on the rebel-held Damascus suburb of Ghouta, killing 1400. Inspectors from the OPCW, which enforces the treaty banning chemical weapons, were able to examine the attack site and confirm the use of sarin.

As a result of that, a deal among world powers, including Russia, forced the Assad government to sign the treaty and declare its stockpile for destruction. The OPCW has confirmed that 94 per cent of what Assad declared was destroyed.

But like UN weapons inspectors in Iraq after the 1991 Gulf war, the OPCW could never quite verify that everything was gone – and like Iraq’s Saddam Hussein before him, Assad has not been cooperating with their efforts to do so, says Zanders.

And Assad has never lost his taste for chemicals. In 2014 he was already dropping barrel bombs of chlorine on civilian areas.

As chlorine is used to purify water, it is not banned under the chemical weapons treaty, although its use as a weapon is. In February the UK-based Human Rights Watch . But chlorine does not produce the telltale pinpoint pupils and other symptoms of sarin seen in Syria this week.

Forensic examinations

Why chlorine?

The northern bald ibis is now extinct in the Middle East. The final member of this genetically distinct Syrian population – a ringed female called Zenobia – was last seen in Palmyra in 2014, a few months before ISIS fighters showed up, says , an Italian conservation biologist who is its most persistent follower. The ibis has since disappeared.

With no mate, the bird’s future was probably doomed even without ISIS, but Zenobia’s story typifies the plight of wildlife in a region engulfed by conflict. The recent troubles there have led to human tragedy, as well as destruction of historical and cultural monuments. Now it appears, nature isn’t spared either.

Across the Middle East and parts of North Africa civil war, poaching to buy guns, and refugees’ urgent need for food and firewood, are extinguishing relic populations of wildlife and wrecking their habitats.

Gazelles flourished in the deserts of southern Libya until recently, says , a rangeland ecologist familiar with the country, who is now based in Mariginiup, Western Australia.

Since the fall of Colonel Gaddafi, hunting parties have been killing wildlife for fun and meat in the lawless badlands of the “wild south”, he says. “No meat is imported to Libya these days, and local herdsmen are hoarding their camels, sheep and goats as capital because they don’t trust the banks,” says Gintzburger. “So people are turning to wild meat.”

Gazelle at great risk

Perhaps at greatest risk is the rhim gazelle (Gazella leptoceros), listed as endangered by the International Union for the Conservation of Nature. The species has seen a “serious decline” in recent years, . Even a decade ago, it calculated that perhaps only a few hundred remained in the wild, mostly in Libya and Algeria. With gun-toting gangs roaming the desert, no zoologists have reported being back to check out how the survivors are doing.

Migrating birds from Europe such as cranes, flamingos, bustards and herons are also being shot in large numbers on coastal wetlands that are no longer guarded, according to the Libya Wildlife Trust.

And the country’s treasured coastal juniper forests are under attack, says of the Kings Park botanic gardens in Perth, Australia. Before the Libyan conflict began in 2011, Miller ran a project with the Omar Al-Mukhtar University in Bayda to protect forests in Jebel, a biodiversity hotspot near Benghazi that is home to the endemic Alexandrian shrew, Crocidura aleksandrisi.

Armed groups have been taking advantage of the chaos since 2011 to fell the forests and take the land for farming, he says. Protected areas in Libya have never been extensive. But those that do exist are under serious threat.

Gintzburger says that in 2008, he fenced a 70-hectare area round the Jbebina oasis near the Tunisian border to protect migrating birds who rested there on their way south. “The last news I got is that this is now totally open to poachers and fighters, shooting ducks, herons, cranes and each other with Kalashnikovs,” he says.

Mali elephants and Yemen’s leopards

The Libyan conflict is threatening wildlife in neighbouring regions, too. UN observers say that weapons for the recent slaughter of a rare population of came from Libya.

Mali’s elephants may all be gone in three years, according to the . And the ivory may be funding Libyan and other Saharan militias.

Things are bad in Yemen, too, which is engulfed by a civil war. There, the Foundation for the Protection of the Arabian Leopard fears for the future of one of the world’s most endangered cats.

Fewer than 200 animals survive in the wild here and in neighbouring Oman. The animal hangs on in the mountains south of the capital Sana’a where the government has been fighting separatists for almost a decade. The last confirmed sighting came 18 months ago when local media published photographs of three dead leopards in the hands of armed poachers.

Syria’s northern bald ibis may already be gone, but much more is at stake. “A big concern is uncontrolled deforestation in the coastal mountains,” says Hassan Partow at the UN Environment Programme in Geneva.

“More than a million people have fled from the conflict zone around Aleppo to the coastal region and the Mediterranean forests,” says Aroub Almasri, a government ecologist at the National Commission of Biotechnology in Damascus. “These people need to fulfil their basic needs in food, electricity and fuel for warming, cooking and pumping water. They have no other choice but to do this in protected areas.”

Forest fires have raged uncontrolled in many coastal forests, she says. The Fronlok Forest, a once-protected area on the border with Turkey now being reclaimed by Syrian forces from militant groups, has suffered badly. “The degree of endemism is high here,” Almasri says, “and many nationally threatened species are found here, including Quercus cerris, an oak native to the region.”

Wardens still try to patrol such places, but lawlessness is rife, Almasri says. “The protected-area teams negotiate daily with local people to minimise damage, but no one can prevent the cutting of trees now.”

Read more: Fences put up to stop refugees in Europe are killing animals; Uncharted waters: Probing aquifers to head off war

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(Image: Zein Al-Rifai/AFP/Getty Images)

Chemical warfare seems to be alive and kicking in Syria and Iraq.

The world breathed a sigh of relief when Syria’s chemical weapons were destroyed last year. But reports have been coming in of the militant group ISIS attacking Kurdish towns in Syria and Iraq with mustard gas, and of ISIS and the Assad regime in Syria using chlorine gas.

Syria, and Iraq before the first Gulf War in 1991, had stockpiles of mustard gas, which causes severe blistering of the skin and lungs. Officially, these have all been removed or destroyed.

But in August, victims of an ISIS attack in northern Syria . Last week, Gerhard Schindler, head of Germany’s Federal Intelligence Service, said ISIS has begun mustard gas attacks against Kurds in north Iraq.

It is possible that ISIS is making the gas itself, Schindler says. One site where it could be synthesised might be the captured labs at the University of Mosul in Iraq.

But chemical weapons experts say it is easier to simply plunder old stockpiles. Mustard gas lasts a long time — it still persists in first world war shells, for example.

And stockpiles are probably still around. A last year based on documents obtained under the Freedom of Information Act found that after the 2003 invasion, US forces found some 5000 pre-1991 chemical munitions in caches across Iraq, including areas now held by ISIS. Some ISIS leaders were members of the former Iraqi regime, says chemical weapons expert Jean-Pascal Zanders, so they might be familiar with how to recycle these.

The Syrian government, meanwhile, and opposition forces other than ISIS have denied using chemical weapons. On 27 August the UN launched a special investigation in an attempt to determine who is using poison gas in Syria.

Stalin is famously supposed to have said that “one death is a tragedy, one million is a statistic”. Identifiable victims seem to trigger empathy and compassion, but many victims seem like cold numbers that do not tug at our heartstrings.

Psychological bears this out: in studies, people tend to feel more empathy and compassion for, and donate more money to, single victims than groups of victims.

This month, after a summer marked by a mixture of apathy and hostility towards refugees despite repeated mass drownings in the Mediterranean, the public mood shifted. The world was brought to tears by an image of a Syrian boy who had perished in an attempt to escape persecution by crossing the sea from Turkey to Europe.

Its publication energised sympathy and support for such refugees, something the deaths of many in the months before had failed to do. So why do we feel sympathy and compassion for single identifiable victims, but not for the many?

According to some scholars, it is because we simply can’t feel compassion for large numbers. As psychologist puts it: “It is impossible to empathise with seven billion strangers, or to feel toward someone you’ve never met the degree of concern you feel for a child, a friend, or a lover.”

Similarly, psychologist has argued that “our capacity to feel sympathy for people in need is limited, leading to compassion fatigue, apathy and inaction”. On this view, it is easy to imagine and attend to the suffering of a single victim, whereas this is difficult, even impossible, for mass victims.

Emotion overload

If empathy and compassion are fundamentally insensitive to large-scale problems, this seems to speak poorly for the usefulness of these moral emotions. Bloom, philosopher and others take this view.

But what if callousness toward mass suffering represents a choice, and not a fundamental constraint? People predict they will feel more compassion as victim numbers increase, which may in turn create concerns about the financial and emotional costs of trying to help so many. Perhaps this will be too expensive, just a drop in the bucket, or be too to think about.

For these reasons, people might try to suppress emotions to avoid these costs. As Mother Teresa put it: “If I look at the mass, I will never act.”

backs this up. Volunteers saw images of either one or eight child refugees from the Darfur region of Sudan. Half were told to expect a request for a financial donation later. We found that the collapse of compassion reverses when this expectation is removed.

We may put such emotional blinkers on consciously, as when we decide to cross the street to avoid someone soliciting for donations; but this can also happen instinctively and without deliberation, as with , possibly to avoid becoming overwhelmed by emotions.

If we realise we are tuning out mass suffering in our own self-interest, we can do something about it. There is a growing body of work in psychology and neuroscience that finds apparent based upon what people want to feel.

To inspire pro-social action in the face of large-scale crises, presenting unsettling pictures of identifiable victims may not be the only path to changing opinion.

Instead, we can ask why people are failing to respond and target their motivations for this. If they are worried about their wallet or emotional overload, then we can try to relieve those worries. My lab is pursuing interventions to see if we can do this.

Although people often lack compassion for mass suffering, indifference is not inevitable.

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