The recent earthquakes in Haiti, Chile, and Turkey offer a gruesome reminder that nature is fickle and powerful, horribly so in the poorest communities in the world. We pray and grieve for and with the millions of people in those three countries who lost their lives, family, friends, homes, jobs, or businesses to these disasters.

Natural disasters appear to have increased dramatically over the past quarter century. According to data from the Center for Research on Epidemiology of Disasters, the number of natural disasters annually worldwide has increased roughly fourfold in the past 25 years, while the number of persons affected by disasters has increased roughly threefold over the same period. While some of this increase is surely attributable to improved monitoring, measurement, and reporting, growth in disasters appears real.

The costs of disasters are borne disproportionately by the poor. The economic cost per disaster is considerably higher as a share of GDP in poorer countries. And people in low-income countries are four times more likely to die in natural disasters than are residents of wealthier North American and European countries.

Earthquakes and resulting tsunamis are the leading killers among natural disasters, accounting for roughly 60 percent of disaster-related deaths. The reason is simple: urbanisation, especially in poor countries. In 2007, the world population became majority urban; urban residents now outnumber rural peoples. And eight of the ten most populous cities in the world sit atop earthquake fault lines (Tokyo, Mexico City, New York, Mumbai, Delhi, Shanghai, Kolkata, and Jakarta). An old adage among earth scientists holds that earthquakes don't kill people—buildings do. The more people pack into more and larger poorly-constructed buildings in urban slums and working-class neighbourhoods, the greater the potential for disaster.

While earthquakes are the biggest killers, droughts and floods are the most common natural disasters, affecting more than 170 million people annually over the past decade, on average. Where earthquakes primarily affect the urban poor, droughts and floods afflict mainly the rural poor, especially farmers and farm workers toiling in remote, rain-fed agricultural regions where bad weather can destroy livelihoods.

We often forget that much of the cost of natural disasters is shouldered by the next generation. In addition to young children's higher mortality rate during disasters, child survivors often emerge physically stunted, cognitively impaired, and psychologically scarred. Malnutrition during crucial pre-school years commonly leads to permanent loss of physical and cognitive capacity. Meanwhile, disaster-affected poor households often must pull children from school so that they can help at home or on the farm as the family struggles to cope with the shock. A recent study by Harold Alderman of the World Bank, John Hoddinott of the International Food Policy Research Institute and Bill Kinsey of the University of Zimbabwe, found that drought in Zimbabwe in the 1980s not only caused malnutrition disproportionately among infants less than two years old—the age most vulnerable to malnutrition—but also that in their young adult years, these victims' drought-caused malnutrition led to reduced schooling and a 14 percent reduction in lifetime earnings.

The good news is that deaths from disasters have increased more slowly than either global population or the number of disasters. Improved preventative measures are saving lives. Deaths from extreme weather events—storms, droughts, floods, and so on—have been substantially mitigated by early warning systems made possible by improved climate prediction and information and communications technologies, as well as operational improvements by humanitarian organizations.

Consider Bangladesh. A generation ago, monsoon flooding routinely brought famine. Yet humanitarian catastrophe has been averted during even worse flooding in the past decade, thanks largely to effective public-private partnerships among NGOs, relief agencies, businesses, and the national government. A cyclone warning system now links the national capital, Dhaka, with radio stations that relay alerts to tens of thousands of village-based volunteers, who then pass along the alert via megaphone to at-risk villagers in coastal areas prone to seasonal flooding during the annual monsoon and cyclone season. Armed with information on which they can act, individual villagers can safeguard their families and seek help from government-permitted agencies and businesses to adjust to rapidly changing circumstances.

Well-informed and properly incentivised human agency has enormous capacity to do good and avert disaster.

The risks associated with natural disasters will nonetheless grow with continued urbanisation and climate change. Hence, there is a need for renewed investment in reducing risk exposure through better engineering and construction, improved agricultural technologies and water management, and better disease control.

And there is reason for hope, even optimism. For example, drought and flood-resistant varieties of rice, maize, and other staple crops are no longer distant dreams; promising cultivars are in on-farm trials now.

Not all risk is reducible, however. Continued improvement in international humanitarian response is equally needed. The Canadian government has been a leader in reforming emergency food aid systems so as to enhance rapid, cost-effective, and culturally-appropriate humanitarian response. Even the United States government, long the foot-dragging behemoth in the global food aid system, is making slow progress.

But it is equally essential to make better use of global capital markets to improve risk transfer through innovation with catastrophe bonds for low-income country governments and novel insurance products tailored to the needs of the world's most vulnerable, such as the new index-based livestock insurance product for poor Kenyan pastoralists launched in January by the International Livestock Research Institute. (Full disclosure: that product was designed by one of my former students, Dr. Sommarat Chantarat, and is run by another of my former students, Dr. Andrew Mude.

The insurance community has an interesting term for natural disasters: "acts of God," indicating that no one can be held responsible for the event that precipitates a loss. This term reflects pre-scientific notions of a wrathful God inflicting retribution on humankind, although it is difficult to reconcile that view with Jesus' teaching of God's unfailing good will towards His wayward children, as in Matthew 5:45: "He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous."

An alternative meaning of the phrase "acts of God" emerges naturally as humanity develops a richer understanding of disasters as the natural, partially predictable consequences of complex earth systems incompletely and imperfectly managed by humans. True "acts of God" are the actions of those who do God's will in responding to disasters: the emergency responders, caregivers, and donors who care for and comfort those who suffer loss—the scientists, engineers, and development professionals who strive to mitigate the risks associated with increasing disasters so that people, especially the poor, do not suffer needlessly.

We do not and will never control nature; that is God's domain. But we can make a great difference in who suffers and how badly from natural disasters, both through our immediate, charitable response to disasters like those that have made headlines in recent weeks and in the science and policies we pursue. Prayer, good works, and investment in science and policy for an ever-changing world are needed in equal measure.