Climate Models: Are They Useful?

Uncertainty Does Not Mean Inaction

Sound decisions can be made about responding to climate change despite significant uncertainties about future climate because high natural variability emerges during the process of modeling Nepal’s climate. It is important to note that Nepal’s climate ranges from subtropical to arctic across the country due to such huge elevation differences across the country. Large variation in local topography and unclear trends in historic annual total rainfall data contribute to this reoccurring and expected level of variability. The need for downscaled regional modeling creates challenges for climate modelers by demanding more precision which general circulation models (or global climate models) lack. Historic data on rainfall patterns do not indicate a clear trend in annual precipitation levels in data from the past 50 years (IDS-Nepal et al. 57).  Monsoon season is just one example of a continuing climate threat to people’s livelihoods calls for immediate risk reduction despite growing uncertainty in how they will change conditions over the long-term. Even when models do not agree on the disruptive behaviors of climate change, natural or cyclical changes in temperature and precipitation remain threats to human security in Nepal because of compounding issues such as widespread poverty and political instability.

A study, by the Integrated Development Society Nepal, consisting of 15 models for monthly rainfall in Kathmandu for the 2040-2060 time period, (at a given emissions level) shows that all of the models agree on increasing rainfall totals in particular months. Compared to the current monthly rainfall totals, all models considered conclude that May, July, and October will have more total monthly rainfall in the future. The July projection shows the greatest potential change in total rainfall ranging anywhere from a 20-45mm increase (IDS-Nepal et al. 59).

Practical Action’s project to create early warning systems demonstrates how rainfall predictions can inform decisions in Nepal. To reduce risk in communities along rivers and in other flood prone areas, Practical Action equips people with the knowledge and the resources to take care of themselves and protect their community against future disasters.

Why Resilience Works

Not only is it less costly to take preventative action, but it is also easier to reduce the risk factors that threaten human security early on rather than intervening later (UNDP 22). A high degree of uncertainty in climate models warrants resilient responses to climate change that will strengthen people’s capacity to cope with a variety of disruptive scenarios. Moreover, resiliency catalyzes community empowerment which build’s people’s capacity to alleviate stress factors within their communities, ultimately helping reduce vulnerabilities from all types of insecurities.

Limitations of Climate Models

One limitation of using climate models for decision-making is that comparing data sets requires matching time periods, levels of data resolutions, and bias corrections. Comparing data sets representing multiple scenarios and model types strengthens analysis and is necessary to account for the range of uncertainty in climate models. Coordinating data collection and preparation procedures for climate modeling requires cooperation at the local, regional, and state levels to ensure that adequate data for downscaled modeling is provided. Increased coordination of precise data collection in Nepal is needed for future studies to cover a wider range of scenarios while capturing large degrees of uncertainty (IDS-Nepal et al. 60-61).

Another limitation of using climate models for decision-making is that monsoons and glaciers add additional layers of uncertainty to future climates. Existing models disagree on potential changes in monsoon season and rainfall at the regional level. Even though an abrupt change in the monsoon could be a tipping point (meaning that it can push the climate system out of balance, causing a larger scale change to the climate system), climate models cannot predict the probability of these large-scale changes. Additionally, temperature increases in Nepal can cause warming which triggers glacial melt water flows. As the amount of ice diminishes, river flows could reduce, but a high degree of uncertainty exists in predicting these changes (IDS-Nepal et al. 66).

Works Cited

IDS-Nepal, PAC and GCAP. Economic Impact Assessment of Climate Change in Key Sectors in Nepal. Kathmandu: IDS-Nepal, 2014.

UN Development Programme (UNDP). Human Development Report. New York: Oxford University Press, 1994.

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