berlin china grow military strength resurgent russia pose grow challenge trans-atlantic alliance come years nato move bolster capabilities could trigger new cold war-style arm race nato report say report complete every four years identify 20 global trend likely affect alliance 2035 range artificial intelligence accelerate technology development climate change grow inequality general denis mercier nato supreme ally commander transformation tell reuters report show high risk major interstate war 2013 report see considerable increase risk major interstate conflict mercier say interview sideline berlin security conference command release companion report map nato respond trend spring document inform 2019 nato political guidance global awareness necessary ready kind scenario mercier say note globalization mean nato weigh factor outside region include military expansion china india easy access technology global nature cyberspace would make easy terrorist network expand challenge current near-monopoly state actors high-tech weapons report say environmental factor would also play big role high rat natural disasters increase open arctic report say well growth global debt erosion trust financial institutions report say defense spend begin increase russia annexation crimea region ukraine 2014 projections call increase 2045. warn increase might create security dilemma start arm race case cold war say compete budget priorities fiscal constraints member state could hamper ability meet nato alliance requirement future mercier say nato already work expand capabilities cyber domain ensure cyber protections bake every weapons system network outset nato permanent attack cyber say note alliance prove quite good protect thus far need remain vigilant nato see grow russia china challenge high risk war