Climate change is a complex and urgent challenge that requires sound scientific knowledge and evidence to inform decision-making and action.
Climate models are powerful tools that can help us understand the past, present, and future behavior of the Earth's climate system, and the potential impacts and risks of different scenarios of greenhouse gas emissions and socio-economic development.
However, climate models are not perfect, and they have uncertainties and limitations that need to be acknowledged and addressed.
A recent study has confirmed that climate models have been getting future warming projections right, and suggested ways to improve their accuracy and usefulness for policy and planning.
How accurate are climate models in predicting future warming?
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Climate models are mathematical representations of the physical, chemical, and biological processes that govern the Earth's climate, such as the interactions between the atmosphere, ocean, land, ice, and biosphere, as per Phys.org.
They are based on well-established laws of physics and empirical observations, and they are tested and validated against historical data.
Climate models can simulate the response of the climate system to natural and human-induced factors, such as changes in solar radiation, volcanic eruptions, greenhouse gas emissions, land use change, and aerosols.
However, these are not exact replicas of reality, and they have sources of uncertainty that affect their projections of future warming.
Some of these uncertainties stem from incomplete or imperfect knowledge of the climate system, such as the feedbacks between clouds, water vapor, and temperature, or the dynamics of ice sheets and sea level rise.
Some uncertainties arise from the inherent variability and unpredictability of the climate system, such as the occurrence of El Niño events or extreme weather events.
Meanwhile, other uncertainties result from the choices and assumptions made by modelers in designing and running the models, such as the spatial resolution, parameterization schemes, initial conditions, and scenarios of future emissions and socio-economic development.
A recent study by Hausfather et al. (2020) has evaluated the accuracy of past climate models in predicting future global average surface temperature over the past half-century.
The study compared 17 global climate models published between 1970 and 2007 with observed temperature data from four independent datasets.
It found that most of the models accurately projected the warming that occurred up to 2017 within a reasonable margin of error.
The researchers also found that the models that best matched observations were those that used realistic estimates of future greenhouse gas emissions and natural factors, such as volcanic eruptions.
The study concluded that climate models are reliable tools for projecting future warming under different scenarios, and that their accuracy can be improved by using updated emissions data and accounting for natural variability.
How useful are climate models for policy and planning?
Climate models are not only useful for scientific research, but also for policy and planning purposes. They can provide information on the potential impacts and risks of climate change for different regions, sectors, ecosystems, and communities, as per UCAR Center for Science Education.
They can also inform the assessment of mitigation and adaptation options, such as reducing greenhouse gas emissions or enhancing resilience to climate hazards.
Moreover, they can support the evaluation of co-benefits and trade-offs between different actions, such as improving air quality or energy security.
However, climate models are not sufficient or definitive sources of information for policy and planning.
They need to be complemented by other types of knowledge and evidence, such as socio-economic and environmental data, stakeholder and expert inputs, and local and indigenous knowledge.
They also need to be communicated and interpreted in a clear, transparent, and relevant way, that acknowledges the uncertainties and limitations of the models, and addresses the needs and expectations of the users.
Climate science is catching up to climate change with predictions that could improve proactive response.
By advancing our understanding of the Earth's climate system and its future trajectories, climate models can help us anticipate and prepare for the challenges and opportunities ahead.
By enhancing our communication and collaboration between scientists, policymakers, practitioners, and communities, climate models can help us co-create solutions that are effective, equitable, and sustainable.
