analysisBy George Richards
Sudan could be liable for environmental damage to South Sudan if it fails to tackle its locust problem.
Whether it is disagreements over oil fees, disputes over borderlands, or accusations of fuelling rebel groups in each other's territory, there is no shortage of tensions between Sudan and South Sudan.
The rhetoric from both sides of the divide is often barbed, and relations between political figures in the two countries are ever heated and precarious.
However, below the radar and far away from the corridors of power and high-level meeting rooms, there is another group of much smaller and humbler actors that may end up being central to even further tensions between the Sudans.
Last week, the United Nations Food and Agriculture Organisation (FAO) announced an expected increase in the numbers of locusts in Sudan in the coming months.
This follows the migration earlier in the year by vast numbers of locusts, who move from their springtime breeding grounds in the deserts of Egypt and the Arabian Peninsula to their summer breeding grounds in the plains of the Sudans.
During this annual migration, locusts are driven into swarms and can fly hundreds of kilometres a day to new regions, posing a huge threat to crops along the way. Each locust can eat its own body weight in vegetation a day, and a swarm can easily tear through a valley of farms leaving no greenery behind.
This year, unusually heavy August rains left vegetation damp, inhibiting locusts' breeding patterns and keeping locust numbers in the Sudan low. But as the vegetation dries out this autumn, the FAO predicts bands of locusts will start to gather again.
The control of locust populations requires a consistent and thorough approach, and is best carried out at the national rather than local level. Such is the speed and range of locusts that a localised response alone can prove sorely insufficient.
Typically, Sudan has had a good track record of containing the effects and potential crop damage caused by these annual locust swarms. But some fear that with Sudan's resources stretched, and little incentive to stop locusts drifting southward across the border, there is a growing risk that the locusts hatching on Sudan's Red Sea coast could end up destroying crops on South Sudanese farms.
Indeed, Sudan's relationship with the Locust and Other Migratory Pests Group - an agency within the FAO which partners with government authorities to bring international expertise and resources to help tackle locusts - has been strained recently.
This March, officials in the Sudanese agriculture ministry accused the FAO of espionage, claiming they replaced an anti-locust instrument with a "spy device".
In the same month, the agriculture minister declared the country free of locusts, only to be contradicted a month later by the FAO which claimed to have identified a 1,000 kilometre-long hatching ground in Sudan's northern provinces. The FAO did, however, also acknowledge the Sudanese government's urgent response to the findings.
The issue came to a head in June when the agriculture ministry filed a formal protest against the FAO's regional office for failing to lend sufficient support, despite the FAO directing $1 million in aid to assist the Sudanese government in its anti-locust efforts.
The challenge in dealing with Sudan's locust problem has been exacerbated by the conflict in the border regions with South Sudan, and by the steady decline in law and order in southern and eastern Sudan, an area that maps almost directly onto the main locust breeding grounds. The Tokar delta on the Red Sea, just north of Eritrea, is one of the hottest and driest places in the world and a particular hotspot for the pests.
Locusts can breed quickly and in vast numbers when unhindered by efforts to control them and it is no coincidence that most warnings issued by the Locust and Other Migratory Pests Group in 2012 were directed at conflict-affected areas.
For example, in Libya, just a year after the 2011 civil war, a locust outbreak was traced to the lawless southwestern border region with Algeria and the Sahel. Meanwhile in Mali, amidst conflict in the north and instability in the capital, the FAO warned of the worst locust infestation since 2005, afflicting not only Mali, but also Chad and Niger.
A locust swarm on the horizon
If Sudan fails to deal with a locust population that goes on to devastate South Sudanese agriculture, tensions between the two countries could escalate even further, adding locusts to the lists of grievances.
However, if certain trends in international law debates are anything to go by, it is also possible that if Sudan's failure to take action directly adds to the environmental damage in South Sudan, the newly-independent country could instead seek legal redress.
Although the framework for holding environmental crimes to account is by no means fully developed, there are signs that international law may begin to take a sterner stance towards perpetrators of environmental destruction.
Various campaigners have urged the International Criminal Court to adopt the crime of "ecocide" as the fifth core crime under its jurisdiction, to accompany genocide, war crimes, crimes against humanity and aggression.
There is also a discernible trend in international law towards bringing environmental threats within the definition of an "act of aggression". For example, the 1977 ENMOD convention prohibits the destruction of the environment for hostile purposes.
Meanwhile under Resolution 687 (1991), which implemented a ceasefire in the First Gulf War, the UN Security Council held Iraq liable for losses arising from its burning of oil wells and spilling of oil into the Persian Gulf during the Iraqi retreat from Kuwait. The Security Council did not cite the 1977 ENMOD convention - Iraq was not a signatory - but nonetheless held Iraq liable.
Of course, one of the major differences between the Iraqi case and the potential Sudanese situation is that Sudan's sin would be one of omission rather than commission.
But again, if certain trends in international law persist, the simple refusal to act against environmental damage could be enough, in a similar way to which failing to act against terrorism can be punished.
Though it is still a way away, the changing international legal landscape could one day mean that South Sudan - suffering environmental destruction wrought by locusts from Sudan - would have grounds on which to bring charges against its northern neighbour.
Indeed, while the world focuses on oil and arms in the Sudans, it could be a small insect - albeit in vast numbers - that tips the balance from precarious peace to more explicit aggression.
George is an associate at Freshfields Bruckhaus Deringer and an advocate at the Asylum Support Appeals Project. He has written for several publications before, including Jadaliyya, Al-Ahram Weekly, MEED and Daily News Egypt.