4.1.3. Heat Accumulation

The increase in HA was visually projected to occur mostly in the western portion of Trinidad under all emission scenarios, with southwestern regions being at high risk due to increasing HA. The change in HA was found to be increasing among the various emission scenarios, with the greatest increases occurring under RCP 8.5, which was expected considering RCP 8.5 assumes that GHG emissions would continue to increase throughout the 21st century. This is similar to other studies conducted on HA in Thailand and Pakistan, where RCP 8.5 yielded the greatest increases in HA over projected time periods (Nasim et al. 2018).

The eastern parts of Trinidad also see an increase in HA, but to a lesser extent than the western portion of Trinidad. All scenarios show that the western regions of Trinidad are projected to be some of the most impacted areas, as they are seen to be the hottest regions in all projections. The southwestern portion of Trinidad is also one of the most impacted, with the HA being very high at the southwestern tip of the island, indicating that this region is at high temperature-related climate change risk and vulnerability. The mountainous regions of Trinidad (the northern, central and southern ranges) were some of the coolest regions. All scenarios also show that there would be a decrease in the coolness of these mountainous regions.

There are a few limitations and uncertainties associated with the methods involved in developing SimCLIM. These include the fact that the pattern scaling and downscaling methods used for each region are based on the best available knowledge of that location and available data. Therefore, the values presented should be viewed as best estimates (Li et al. 2017). However, the climate data used within SimCLIM are considered legitimate (according to the IPCC and country-specific standards), wide-ranging (high-resolution data), defensible (scientifically robust), and actionable (Li et al. 2017). This heat accumulation information derived from SimCLIM can therefore be considered fit for adaptation and mitigation planning. Additionally, the maps generated using all four RCPs (emission scenarios) similarly indicate that the western and southwestern portion of Trinidad is at most temperature- and heat-related risk. It is therefore imperative that action is taken within these regions in order to reduce further impacts, which can lead to human morbidity, mortality, and a range of ecological impacts.

This study highlights the western and southwestern regions of Trinidad as being most vulnerable and at risk due to heat related impacts. It is therefore important that adaptation strategies are implemented for these particular regions in order to minimize impacts. The majority of the population of Trinidad resides within the western portion of Trinidad, putting them at high heat-related risk and vulnerability.

#### *4.2. Threats Posed by Extreme Heat*

#### 4.2.1. Threats to Human Health

There are a number of occupational health concerns associated with increased heat. Psychomotor, perceptual, and cognitive performances in the workplace are all affected due to increases in heat. These all exacerbate the risk of injuries on the job (Kjellstrom et al. 2016; Borg et al. 2021). There are established standards for workplace heat stress management according to the International Organization for Standardization (ISO) (Parsons 2018). However, according to the Intergovernmental Panel on Climate Change (IPCC), some parts of the world have already notably exceeded the ISO level for safe work activity during the hottest months of the year. As heat increases, job exertion, heat stress, and heat exhaustion also increase, and this reduces the amount of work that can be carried out, particularly by outdoor workers, during the hottest periods of time (Kjellstrom et al. 2016; Parsons et al. 2021). This can potentially reduce the overall productivity of a country and thus affect the economy.

The extreme heat caused by climate change poses significant threats to human health in a myriad of ways. Indirect adverse health effects such as air pollution due to wildfires coupled with direct effects of extreme heat on the human body often lead to morbidity and mortality. These effects tend to disproportionately affect vulnerable populations of society, including, but not limited to, low-income individuals, disabled persons, chronically ill persons, and the elderly. Globally, the negative health impacts of extreme heat have been evident as heat waves in July 2022 affected Europe and the USA, which put stress on societies and increased mortality risk (Nature 2022). One study considered 43 countries during the period 1991–2018 and determined that 37% of "warm-season heat-related deaths" could be attributed to anthropogenic climate change (Vicedo-Cabrera et al. 2021). Furthermore, increased mortality due to climate warming is evident on every continent (Vicedo-Cabrera et al. 2021).

When increased heat leads to wildfires, the subsequent emissions in the smoke produced result in adverse effects to human health and may lead to death through smoke inhalation (Guo et al. 2019). In Trinidad, as discussed previously, there have been wildfire events that exacerbated asthma in students as well as those that caused the death of a 67-year-old man due to smoke inhalation (Felmine 2019).

If the human body is subjected to increased temperatures and is unable to cool itself efficiently, a person may suffer from heat stress with a spectrum of symptoms such as nausea, excessive sweating, headache, muscle cramps, and collapse. Heat stress can be categorized as heat exhaustion, where a person can take measures to cool down; heat injury, where organ damage may occur; or life-threatening heat stroke, where medical assistance is required (Morris and Patel 2021). In 2022, the year's highest recorded temperature in Trinidad was 34.2 ◦C in Piarco (Hosein 2022). Notably, the threat of heat stress is increased in urbanized areas in Trinidad such as the city of Port of Spain due to the surface urban heat island. Furthermore, there is increased morbidity and mortality among vulnerable groups such as children, older persons, pregnant persons, and disabled persons, as these groups are typically more sensitive to heat. Additionally, due to physical activity, athletes and individuals who work outdoors such as on construction sites are also at higher risk of heat stress.

The observed impacts of climate change include adverse health effects across geographical regions and are largely negative on all scales. Climate change has been positively associated with an increase in illnesses such as dengue, chikungunya, and Lyme disease. Additionally, due to heavy rainfall and flooding events, there are observed increases in vector- and waterborne diseases in affected regions. Furthermore, increased heat due to climate change has resulted in increased respiratory diseases from ozone air pollution, smoke associated with wildfires, and shifting pollen seasons (IPCC 2021). Extreme heat due to climate change has also negatively impacted the mental health, quality of life, cognitive performance, and happiness of individuals who are affected by heatwaves. Climate change has also been observed to contribute to food insecurity through extreme weather and climate events such that populations consume inadequate food. This results in malnutrition, which disproportionately affects children and pregnant women and results in disease susceptibility in low- and middle-income populations (IPCC 2021).

#### 4.2.2. Droughts

Extreme heat levels result in an increased frequency and intensity of droughts which are prolonged periods of abnormally low precipitation leading to water shortages. Droughts can be classified as short-term or long-term. Short-term droughts tend to affect agriculture and result in wildfires, while long-term droughts affect water resources and lead to ecological losses (Gamelin et al. 2022). In recent years, there has been a notable increased propensity of droughts globally, resulting in lowered crop yield, increased food prices, and the lowered production of hydropower (European Commission 2022; Moens 2022).

In Trinidad and Tobago, although drought is a natural phenomenon, it has been noted that droughts have been becoming more severe and less predictable, leading to adverse effects on the water resources and agriculture (Beharry et al. 2019). Trinidad and Tobago experienced notable droughts in 1997–1998 and 2002–2004; however, in 2009–2010, the country experienced a severe, wide-spread drought with rainfall reaching 25% of expected levels. This resulted in a 6.9% increase in food prices, with cattle livestock being affected by disease and two of the reservoirs recording lower than average levels (Beharry et al. 2019).

In 2018–2019, Trinidad and Tobago, along with many other Caribbean nations, was placed on drought watch, with the Water and Sewerage Authority (WASA) advising the public to conserve water due to reduced rainfall levels (Government of the Republic of Trinidad and Tobago 2019). During this time, one of Trinidad and Tobago's largest rice producers noted that due to the lack of water, he was forced to scale back production from 300 acres of rice planted to 10 acres of rice as of January 2019 (Paul 2019). Agricultural Society President Dhano Sookhoo urged the public to prepare for increased food prices and the non-availability of food. Sookhoo also predicted that the country would be driven to import more food that would usually have been grown locally (Paul 2019). According to Kishan Kumarsingh, Head of the Multilateral Environmental Agreements at the Ministry of Planning and Development, these weather extremes experienced in 2018 and 2019 may become the norm as the global temperature increases (Doodnath 2020).

#### 4.2.3. Wildfires

Wildfires are unplanned fires in a natural environment such as forests or grasslands. Since wildfires are driven by dry, organic material that can ignite and burn when heated, the extreme heat, drought and low relative humidity generated by climate change exacerbate this natural phenomenon (UNFCCC 2022). With business-as-usual circumstances, the number of wildfires is expected to increase by 14% by 2030, 30% by 2050, and 50% by 2100 (UNFCCC 2022). Not only does climate change exacerbate wildfires but wildfires exacerbate climate change, creating a positive feedback loop (UNFCCC 2022). The ramifications of wildfires include adverse health effects due to smoke inhalation, the economic burden of rebuilding areas ravaged by wildfires, watershed degradation, soil erosion, and loss of biodiversity (UNFCCC 2022).

Historically, areas throughout Trinidad and Tobago, particularly along roadways and hillsides, have been known to burn during the dry season from January to May (ODPM 2011). However, increased wildfire events have been noted to correspond with periods of drought due to increased heating. In 2019, during a period of drought, a notable wildfire incident occurred in Princes Town near two primary schools, leading to the forced evacuation of over 900 students (de Silva 2019). It was reported that the smoke from the fire affected students with asthma, and a galvanized water line was damaged by the fire and subsequently ruptured (de Silva 2019). In some cases, such as in another wildfire in La Romaine of 2019, the effects have been fatal. A wildfire along Allahar Street resulted in the death of a 67-year-old man and the destruction of his house. According to the autopsy report, he died from smoke inhalation (Felmine 2019). As global temperatures continue to increase, there will be an increased frequency and intensity of droughts and resulting wildfires.
