The Globe and Mail reports in its Wednesday edition that the years-long trade wrangling and uncertainty that faced Britain in the wake of the Brexit vote was a "cakewalk" compared with what Alberta's separation from Canada would involve. The Globe's Emma Graney writes that is the assessment of a new report about the economic implications of secession. Trevor Tombe, a University of Calgary economist, penned the report for the Calgary Chamber of Commerce. Released Tuesday in the midst of a heated campaign over provincial separation, the analysis concluded that investment in Alberta could fall between 12 and 18 per cent if the province pursues secession, and coffers risk swinging from a $19-billion annual surplus to a $9billion deficit. Prof. Tombe's report warns just how trade-exposed Alberta's economy is, and the extent to which jobs and investment in the province rely on good relationships with Canada and other countries. The report comes alongside an open letter, signed by 11 high-profile executives in the province urging Albertans to choose to remain in Canada. Among the signatories are AltaGas chief executive officer Vern Yu; Nancy Southern, CEO at Atco; AltaLink president Paul Lee and Dean Setoguchi, CEO at Keyera.