Climate change is no longer a global discourse far removed from everyday life. For farmers in the highlands around Lake Toba, the changes are already tangible, from increasingly unpredictable planting seasons to harvests that are increasingly vulnerable to failure. The scientific article titled Climate Change Adaptation Knowledge Among Rice Farmers in Lake Toba Highland, Indonesia, published in June 2025 in the journal Sustainability, discusses this phenomenon in depth. The study was written by Rizabuana Ismail, Erika Revida, Suwardi Lubis, Emmy Harso Kardhinata, Raras Sutatminingsih, Ria Manurung, Bisru Hafi, Rahma Hayati Harahap, and Devi Sihotang.

Their research focus is simple yet crucial: how rice farmers in the Lake Toba highland area adapt to the impacts of climate change, and how the traditional knowledge that has long served as a guide is beginning to change or even be abandoned. At the start of the study, they emphasized how climate change has a direct impact on the agricultural sector in Indonesia. In 2023, for example, financial losses due to climate change were estimated to reach IDR 115.53 trillion, with IDR 19.94 trillion of that coming from the agricultural sector.

In this study, 130 rice farmers were purposively selected from two different areas in Samosir Regency: Harian Subdistrict, which uses irrigation based on the Efrata waterfall, and Pangururan Subdistrict, which does not have a permanent irrigation system and relies on rainfall or water pumps from Lake Toba. These geographical differences provided an opportunity to compare the adaptation strategies of farmers on irrigated land with those who rely only on rainwater.

According to Rizabuana Ismail, the selection of the two locations was indeed deliberate to capture more complete adaptation dynamics. He explained, “Differences in water access affect how farmers understand and respond to climate change. By comparing the two, we can see clearer patterns.”

The results showed that farmers’ awareness of climate change is quite high. Most recognized a decrease in rainfall, an increase in temperature, and a reduction in river discharge over the past ten years. For non-irrigated farmers, these impacts are felt more severely because water availability truly becomes the determining factor. Almost all non-irrigated farmers (98.5%) reported having experienced prolonged drought, compared to 66.1% of irrigated farmers.

This awareness then encouraged the emergence of various adaptation strategies. Irrigated farmers tended to continue planting rice, although some tried diversification by planting corn. Conflicts over water also occurred when the discharge from the Efrata Waterfall decreased during prolonged dry seasons. Some farmers even guarded irrigation channels at night so that the water flow would not be diverted by others.

Meanwhile, non-irrigated farmers relied more on water pumps to irrigate fields near Lake Toba. However, the pump rental cost of IDR 30,000 per hectare made them think twice. Not infrequently, land was left fallow during the dry season because the cost of irrigation was greater than the harvest obtained. In extreme conditions, they switched to planting short-term crops such as corn, long beans, or ginger, which are more drought-tolerant.

This situation gave rise to a new social phenomenon: envy among farmers. Those whose land is close to Lake Toba can still utilize pumps, while those in the hills truly rely only on rain. This difference in water access creates inequality in adaptive capacity. For some farmers, this generates social jealousy that could potentially trigger conflict.

This study also highlights the role of farmer groups. More than 90 percent of respondents were members of farmer groups, mainly to obtain subsidized fertilizer or better rice seeds. However, the role of farmer groups in providing information on climate change remains minimal. As many as 71.4 percent of farmers said their groups had never disseminated climate change information. As a result, most farmers (87.7%) planted rice without referring to formal climate data, but instead based on personal experience and direct observation.

One important finding is the declining reliability of traditional knowledge. In the past, Batak Toba farmers read natural signs to determine planting time: wind direction from Lake Toba, fish behavior in the lake, or certain sounds from nature. Now, however, those signs are increasingly difficult to predict. Almost all farmers (96.7%) stated that seasonal patterns were no longer regular. For example, rain that usually fell in September in recent years only arrived in October. Consequently, planting patterns that used to be twice a year are now often only once.

Although traditional knowledge is increasingly eroded, it does not mean that farmers have lost their creativity. They develop experience-based strategies. For instance, some farmers advance planting time to anticipate delayed rains, or harvest earlier when strong winds threaten to topple rice stalks. Here it is evident that adaptation proceeds more as a practical response rather than based on traditional predictions.

Rizabuana Ismail views this phenomenon as a reflection of farmers’ resilience. According to him, the loss of some traditional knowledge does not mean weakness, but rather a transition toward strategies more suited to current climate conditions. “Farmers always learn from experience. They may no longer rely on the natural signs they used to, but they still find ways for their fields to produce,” he explained.

In terms of yields, the differences between irrigated and non-irrigated farmers are also significant. For irrigated farmers, crop failure usually means reduced yields, but there is still something to harvest. In contrast, for non-irrigated farmers, crop failure can mean nothing at all—no yield whatsoever. This condition makes them more vulnerable to large losses and even forces them to seek additional work as farm laborers elsewhere.

The study then offers important recommendations. First, policies need to be more sensitive to geographical differences. Government support cannot be uniform; it must be tailored to field conditions. Second, it is necessary to strengthen the capacity of farmer groups as climate information hubs, not merely places for distributing fertilizer and seeds. Third, integration between modern science and local knowledge is needed so that adaptation processes become more effective.

These findings are also in line with global trends. Many international studies show that smallholder farmers in various parts of the world adapt in their own ways, regardless of whether they believe in the scientific concept of climate change or not. Daily real-world experience is more convincing than scientific reports that often feel abstract. The same applies in the Lake Toba highlands. Farmers do not wait for climate data from the government; they act directly based on what they see and experience.

In this context, the research conducted by Rizabuana Ismail and the team becomes very important. It not only documents what farmers have done but also opens a space for discussion on how traditional knowledge can be preserved without sacrificing the need for more practical adaptation. Such an approach shows that science can run side by side with local wisdom rather than negating each other.

At the end of his explanation, Rizabuana Ismail offered a reflection: “Our farmers have extraordinary resilience. Climate challenges may become heavier, but they continue to seek a way. Our task as researchers and policymakers is to ensure that effort is supported, not left on its own.”

In other words, the story of farmers in the Lake Toba highlands is a story of human resilience in the face of uncertainty. The traditional knowledge that once served as a guide may now be fading, but the spirit to endure shines even brighter. This research reminds us that adaptation is not merely about technology but also about courage and togetherness in confronting change.