"Previous country-level research assessing climate change impacts and adaptation either focused on economy-wide estimates or sector-by-sector analysis, without looking at the bigger picture," says Kenneth Strzepek, one of the lead authors of the study and a research scientist at MIT's Joint Program on the Science and Policy of Global Change. "By looking at the interplay between different sectors and within the economy, we are able to evaluate the indirect effects and interactions that can occur that are often not captured."
As a case study (view PDF), the researchers apply their technique to Ethiopia — the second most populated country in Sub-Saharan Africa. They look at three key sectors: agriculture, road infrastructure and hydropower.
"These sectors were selected because of their strategic role in the country's current economic structure and its future development plans," Strzepek says.
Agriculture accounts for about 46 percent of the GDP in Ethiopia and is almost entirely rain-fed. Variability in temperature and rainfall will have major impacts on this crucial industry. The researchers found that with a temperature increase of two degrees Celsius, more intense drought and floods will cause a drop in crop production — triggering reductions in income, employment and investments.
Frequent and intense flooding will also damage Ethiopia's road infrastructure — the backbone of the country's transportation system and a needed link in the agricultural supply chain. The researchers found that flooding brought on by climate change will increase maintenance costs by as much as $14 million per year for the existing road network, which is expected to grow dramatically in the next 40 years.
The intense variability of precipitation will also greatly impact the country's hydropower and associated reservoir storage, which could provide energy, irrigation and flood mitigation. Because there is currently little installed hydro capacity in Ethiopia, the model showed few climate change impacts. But in the coming years, the government plans to invest heavily in this sector, meaning there could potentially be significant impacts to this sector as well.
Additionally, the researchers found that there would be an increased demand for water across sectors and create challenges for policymakers to effectively distribute this important resource. For example, Ethiopia plans to expand irrigated agriculture by 30 percent by 2050. The researchers found that some of the irrigation demands will be unmet, placing demands on other sectors requiring water resources.
"This research makes clear the impact droughts, floods, and other effects brought on by climate change can have on major financial sectors and infrastructure," Strzepek says. "For Ethiopia, we find that one of the best defenses against climate change is investment in infrastructure for transportation, energy and agriculture. By building up these sectors, the government will be able to enhance the country's resiliency."
He continued, "In predicting the outcomes of future water, infrastructure and agriculture projects, we were able to test the effectiveness of policies. This gives decision-makers in these countries, as well as international organizations, the information they need to continue to grow, develop and plan for the future with climate change in mind."
Planning for climate change is essential, Raffaello Cervigni, a co-author of the study and lead environmental economist at the World Bank, writes in a recent blog post.
"Addressing climate change is first and foremost a development priority for Africa … If no action is taken to adapt to climate change, it threatens to dissipate the gains made by many African countries in terms of economic growth and poverty reduction over the past ten years," he writes.
But, he continues, "a harsher climate need not be an impediment for Africa's development," if we can come together to address these challenges.
The integrated approach used by the authors is now being applied to studies on the costs of adapting to climate change in Ghana and Mozambique, as well as Vietnam. Others have replicated the approach to help other countries calculate the costs of adaptation.