RESUMO
Quasi-experimental methods increasingly are used to evaluate the impacts of conservation interventions by generating credible estimates of counterfactual baselines. These methods generally require large samples for statistical comparisons, presenting a challenge for evaluating innovative policies implemented within a few pioneering jurisdictions. Single jurisdictions often are studied using comparative methods, which rely on analysts' selection of best case comparisons. The synthetic control method (SCM) offers one systematic and transparent way to select cases for comparison, from a sizeable pool, by focusing upon similarity in outcomes before the intervention. We explain SCM, then apply it to one local initiative to limit deforestation in the Brazilian Amazon. The municipality of Paragominas launched a multi-pronged local initiative in 2008 to maintain low deforestation while restoring economic production. This was a response to having been placed, due to high deforestation, on a federal "blacklist" that increased enforcement of forest regulations and restricted access to credit and output markets. The local initiative included mapping and monitoring of rural land plus promotion of economic alternatives compatible with low deforestation. The key motivation for the program may have been to reduce the costs of blacklisting. However its stated purpose was to limit deforestation, and thus we apply SCM to estimate what deforestation would have been in a (counterfactual) scenario of no local initiative. We obtain a plausible estimate, in that deforestation patterns before the intervention were similar in Paragominas and the synthetic control, which suggests that after several years, the initiative did lower deforestation (significantly below the synthetic control in 2012). This demonstrates that SCM can yield helpful land-use counterfactuals for single units, with opportunities to integrate local and expert knowledge and to test innovations and permutations on policies that are implemented in just a few locations.
Assuntos
Conservação dos Recursos Naturais/legislação & jurisprudência , Florestas , Brasil , Mudança Climática/estatística & dados numéricos , Conservação dos Recursos Naturais/economia , Conservação dos Recursos Naturais/estatística & dados numéricos , Ecossistema , Modelos Estatísticos , Política Pública/economia , Política Pública/legislação & jurisprudência , Árvores , Clima TropicalRESUMO
The claim that nature delivers health benefits rests on a thin empirical evidence base. Even less evidence exists on how specific conservation policies affect multiple health outcomes. We address these gaps in knowledge by combining municipal-level panel data on diseases, public health services, climatic factors, demographics, conservation policies, and other drivers of land-use change in the Brazilian Amazon. To fully exploit this dataset, we estimate random-effects and quantile regression models of disease incidence. We find that malaria, acute respiratory infection (ARI), and diarrhea incidence are significantly and negatively correlated with the area under strict environmental protection. Results vary by disease for other types of protected areas (PAs), roads, and mining. The relationships between diseases and land-use change drivers also vary by quantile of the disease distribution. Conservation scenarios based on estimated regression results suggest that malaria, ARI, and diarrhea incidence would be reduced by expanding strict PAs, and malaria could be further reduced by restricting roads and mining. Although these relationships are complex, we conclude that interventions to preserve natural capital can deliver cobenefits by also increasing human (health) capital.
Assuntos
Conservação dos Recursos Naturais , Ecossistema , Saúde Pública , Brasil/epidemiologia , Conservação dos Recursos Naturais/métodos , Conservação dos Recursos Naturais/estatística & dados numéricos , Diarreia/epidemiologia , Diarreia/prevenção & controle , Humanos , Incidência , Controle de Infecções , Malária/epidemiologia , Malária/prevenção & controle , Saúde Pública/estatística & dados numéricos , Regressão Psicológica , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/prevenção & controleRESUMO
Scholars have made great advances in modeling and mapping ecosystem services, and in assigning economic values to these services. This modeling and valuation scholarship is often disconnected from evidence about how actual conservation programs have affected ecosystem services, however. Without a stronger evidence base, decision makers find it difficult to use the insights from modeling and valuation to design effective policies and programs. To strengthen the evidence base, scholars have advanced our understanding of the causal pathways between conservation actions and environmental outcomes, but their studies measure impacts on imperfect proxies for ecosystem services (e.g., avoidance of deforestation). To be useful to decision makers, these impacts must be translated into changes in ecosystem services and values. To illustrate how this translation can be done, we estimated the impacts of protected areas in Brazil, Costa Rica, Indonesia, and Thailand on carbon storage in forests. We found that protected areas in these conservation hotspots have stored at least an additional 1,000 Mt of CO2 in forests and have delivered ecosystem services worth at least $5 billion. This aggregate impact masks important spatial heterogeneity, however. Moreover, the spatial variability of impacts on carbon storage is the not the same as the spatial variability of impacts on avoided deforestation. These findings lead us to describe a research program that extends our framework to study other ecosystem services, to uncover the mechanisms by which ecosystem protection benefits humans, and to tie cost-benefit analyses to conservation planning so that we can obtain the greatest return on scarce conservation funds.
Assuntos
Conservação dos Recursos Naturais/economia , Ecossistema , Pobreza/economia , Brasil , Sequestro de Carbono , Análise Custo-Benefício , Costa Rica , Meio Ambiente , Política Ambiental/economia , Florestas , Humanos , Indonésia , Modelos Econômicos , TailândiaRESUMO
The private demand for a hypothetical vaccine that would provide lifetime protection against HIV/AIDS to an uninfected adult was measured in Guadalajara, Mexico, using the concept of willingness to pay (WTP). A 91-question survey instrument was administered by trained enumerators employing contingent valuation techniques to 234 adults, aged 18-60. Our estimates of private demand indicate that individuals anticipate sizable personal benefits from such a vaccine, and that they would be willing to allocate a substantial portion of their income to be protected in this way from HIV infection. A conservative estimate of the mean WTP of adults in the Guadalajara sample is 6358 pesos (669 US dollars) and the median is 3000 pesos (316 US dollars). A multivariate statistical analysis of the determinants of individuals' WTP shows that individuals with higher incomes, with spouses or partners, and with higher perceived risks of becoming infected with HIV are willing to pay more for the vaccine. Older respondents are willing to pay less. These results suggest that there is likely to be a potentially large private market for a HIV/AIDS vaccine in the middle-income developing countries such as Mexico. These findings have important implications both for the level of R&D effort that is devoted to a vaccine and, assuming these efforts are successful, for future policies to make the vaccine available to the public.