The Swiss Assassin

Peter Villiger is Swiss, a Somali refugee who appears to be an independently wealthy and well-travelled author. This hides his true role as a high-tech hitman working for a secretive, UN-sponsored organisation targeting terrorists and warlords that international law has failed to either control or punish. With biomimetic drones and tailored toxins as the tools of his trade, he has flexibility to make punishment fit the crimes involved - with assassinations documented in videos that strike fear into those who previously considered themselves above the law.
The challenges change when the list of targets is suddenly expanded to include white-collar criminals who, although not personally involved in killings, are responsible for huge numbers of deaths through fomenting and arming conflicts. Unlike the war zones of past assassinations, Peter is now operating in the luxurious, decadent microcosms in which the mega-rich live, remote from the multitudes suffering from accelerating climate change.
His wife and her hedonistic twin sister accompany him on apparently straightforward operation in Bali, which unexpected uncovers a global conspiracy to facilitate and benefit from environmental degradation. With the help of the sisters, Peter finds that this threat has links to the very highest level of his own organisation, with a trail leading to the Seychelles and a meeting of the upper echelons of a cabal with the power to influence the tipping points that control socioeconomic change.
As his employer is compromised, Peter solicits the support of a local intelligence agency for the key job of hacking a database in Switzerland, which will provide the only possible way of stopping this nefarious plan. With the help of his sister-in-law, the Swiss coordinate a response to the threat at UN level, freeing Peter to take over the job of assassinating all of the remaining key conspirators.
The question is, can this be done without actually catalysing a pre-programmed apocalypse?