Agriculture's role in reducing greenhouse-gas emissions could take a backseat to debate about the higher costs farmers could face under the climate legislation as the Senate Agriculture Committee hears from farm groups and key officials in the Obama administration on Wednesday. Republican senators throughout the ranks of the Agriculture Committee have made it clear since last week that Secretary of Agriculture Tom Vilsack and Environmental Protection Agency Administrator Lisa Jackson had better come armed with detailed data on what kind of costs farmers may face. Some senators want detailed information broken down by commodity and state. The climate bill passed...