The Bank of Canada on Wednesday held its key overnight interest rate at 1 percent because it said it needs to provide stimulus to a slow-moving economy. The central bank said that global conditions remain weak and that growth in previously hot emerging markets is cooling faster than previous expected, although the Canadian economy continues to grow moderately. Canadian interest-rate policy has not changed in two years, but the bank is leaning toward tightening, which means that the next rate change, whenever it comes, is more likely to be toward higher interest rates. The central bank said it expects Canadian economic growth to accelerate through 2013.