And how to prevent the worst of the damage. By Raymond C. Offenheiser Already, more than 250 million people around the world are affected by climate-related disasters each year. A new Oxfam report released today forecasts that those droughts, floods, and storms are likely to become much more numerous and much worse over the next five years. We project that the number of people affected by climate-related humanitarian disasters will rise more than 50 percent by 2015, leaving agencies such as Oxfam scrambling to meet the resulting need. Given the scale of the threat, overhauling the world's emergency response and humanitarian aid systems is no longer optional, if it ever was. The time for debate about whether to focus on preventing climate change versus adapting to it is long past. It's imperative that we start preparing for the future, even as we try to stop it. Recent disasters have shown that the most effective aid is preemptive, preparing a community long before the calamity has struck. And by mitigating a storm's effect, preventive action will pay for itself many times over -- more than four times, according to the latest studies. Poor communities -- that will be the most vulnerable to disaster -- are the places to start preparing. With help, these communities can design and implement adaptation strategies such as drought-resistant seeds, food banks, coastal tree barriers, and mosquito nets. Such cost-effective projects have the added benefit of helping vulnerable communities overcome poverty in the long term. Adjusting to the impact of climate change can also create green jobs and economic opportunities. Businesses in developed countries can respond to growing markets for climate-change-resistant technologies such as water pumps, filtration devices, and irrigation equipment, as well as create early warning systems to forecast storms or floods in order to prevent the worst of the damage. In the United States, this process can begin as part of the proposed American Clean Energy and Security Act of 2009. The bill, which paves the way for a transition to a low-carbon energy economy, could provide real resources to help the poor adapt to the unavoidable impacts of climate change. The final goal is a world where carbon dioxide emissions are reduced and impacts don't reach even more catastrophic levels. A cap-and-trade system with 100 percent auctioning of allowances can not only curb greenhouse gas emissions, but also generate the necessary revenue to help ease the transition for low-income energy consumers to clean energies; invest in green-collar jobs, energy efficiency, and renewable energy; and help poor and vulnerable communities around the world adapt. Global security may depend on it. Forty-six countries are at "high risk of violent conflict" if and when climate change exacerbates traditional security threats, according to another recent report. Increased competition for scarce resources and displacement following storms make disasters even more dangerous. Failing to act now will mean much greater costs later, not just in dollars and cents, but also in human suffering, conflict, and lives lost. Raymond C. Offenheiser is president of Oxfam America.