• Energy Research
• 2025-2025close
• 13. Climate action close
• English close

Global lakes hold about 87% of the freshwater. However, climate change has posed a severe threat to these freshwater resources. Evaporation (E) is a major water loss from lakes, and the strong coupling between lake E and changes in atmospheric conditions in a warming climate leads to temporal and spatial variability in water loss through E, making it challenging for water resource management. This dissertation examines such spatiotemporal variability in global lake E in response to climate change, investigates its environmental controls, and identifies regions with large sensitivities to climate changes. Using a state-of-science Lake, Ice, Snow, and Sediment Simulator (LISSS) that is a lake model within the Community Land Model (CLM), it is shown that the large spatial variability of global lake E is modulated by the vapor pressure difference (e_D) between lake surface and overlying air. The e_D also causes higher nighttime lake E, which contributes more to the spatial variability of global lake E than daytime lake E. The performance of the Penman method (PM) is also evaluated against observations and the LISSS modeling results in estimating global lake E. It is shown that the PM overestimates lake E due to a strong bias in the net radiation (Rn) and lake water heat storage (G). Using the LISSS simulated Rn and G in the PM, however, the PM performance is largely improved and the PM E becomes comparable to the LISSS E. The global lake E trend over 1951 - 1978 is analyzed, which shows a decreasing E trend. Such a declined global lake E was largely caused by the decreased downward shortwave solar radiation. The global lake E was switched from the decreased trend over 1951-1978 to an increased trend over 1981-2016 with an accelerated trend of 0.76 mm yr-1. The tropical, arid, and temperate climate regions lakes contribute 66% to the increasing trend despite covering only 38% of the global lake surface area. Such a change in the global lake E trend was attributed to the increased vapor pressure deficit in a warmer climate. The model projection indicates that the mean global lake E will increase by 13% by the end of the 21st century under the Representative Concentration Pathway (RCP) 8.5 emissions scenario, relative to the 1985-2000 mean global lake E. The changes in lake E are expected to be more pronounced in North America, equatorial South America, Africa, northern Europe, Siberia, and Southeast Asia due to increased interannual variability. The results in this dissertation indicate that the widespread but heterogeneous increase in the global lake E threatens the crucial socioeconomic benefits that lakes provide to human society.

The increasing wildfire activity in the past few years has been devastating, setting negative records in many states and regions around the world, especially in North America. Power systems have been impacted by wildfires in many ways, even in regions located hundreds of kilometers away from high-risk zones, depending on wind speed and direction conditions, the stemming smoke of wildfires may significantly impact the air quality and reduce the solar PV generation, and forcing several utilities to rely on PSPS programs to mitigate wildfire risks. Thus, power system operators must ensure reliability and resilience across power generation, transmission, and distribution while minimizing carbon emissions that can harm even more the air quality of the affected communities during wildfire events. Furthermore, a cost-effective power system expansion planning solution in regions with increased wildfire risk is achieved by placing ESSs and new transmission/distribution lines while taking into account their availability given the increasing number of PSPS events. This research aims to analyze the impact of wildfire activity on the electrical system's planning and operation, by analyzing the impact of the 2020 wildfire season on renewable energy in Washington state, focusing on variables that directly impact the wind and photovoltaic power. After that, efforts are made to approach the expansion planning of power transmission and distribution systems under wildfire risk, considering sitting and sizing of ESS as an alternative, with a compliance check on unbalanced power flow and system operating limits. The resulting models are a MILP optimization problem, and simulation experiments are performed to validate the effectiveness of the proposed formulation using different High Fire-Threat District Tier Zones based on real-world data from electric utilities in California.

YouTube, a website for sharing videos online, is widely popular around the world and is also frequently used as a source of information on science and environmental subjects. For more than fifteen years, climate change advocacy groups have been actively spreading awareness about the issue through social media platforms such as YouTube. They have been creating videos that present up-to-date statistics and information on environmental policies, showcasing their ongoing campaigns, and most significantly, producing advertisements related to climate change. However, only little is known about how the audience perceive these advertisements, what role does emotion play in engaging the audience through views, likes and comments. We specifically wanted to explore the nature of emotional flow in climate change video ads and whether shifts in emotions in the ad content results in greater audience views, likes and comments, in other words, audience engagement. The study's findings indicate that including emotional shifts in advertisements leads to a significantly greater number of views, likes, and comments compared to ads that do not include emotional shifts. Additionally, emotions such as fear, guilt, anger, sorrow, and surprise were identified as crucial factors in effectively engaging audiences through views, likes and comments with climate change ads.