Walking through the rice paddies of coastal Bangladesh, the beauty envelopes my senses. In sharp contrast to the urban din of Dhaka or Khulna, no chorus of car horns punctuates the air. Instead, the deltas spilling into the Bay of Bengal send salty breezes sweeping across the plants like a whisper. Farmers construct wooden stands in their fields for snacking birds to peruse bugs—an all-natural pesticide, they joke—adding splashes of bright blue to the cascading greens.

A rice field in southern Bangladesh featuring bird perches made of wood.

Yet this quiet loveliness hides a disturbing truth: the villages sit on the front line of climate change’s most devastating impacts. Reckless behavior by rich countries has left the residents’ livelihoods—and their very lives—at the mercy of a warming planet that has already started to wreak havoc on this vulnerable population. Without drastic government action, households have no recourse but to adapt to their shifting local environment themselves.

Soil with salt visible on the surface. I visited Bangladesh to study how farmers learn about climate change, a necessary step for adaptation. Consider, for instance, the salt content of soil, a critical component of the rice production function. As sea levels and temperatures rise, salinity can increase via contaminated ground water, flooding, and evaporation, to name a few factors. Too much will kill the crop. Farmers lack access to a technology that accurately measures the amount of salt. Instead, households rely on imperfect and blunt rules of thumb that cannot detect incremental shifts.

The example of salinity highlights a tremendous obstacle to accurately learning about climate change: the universal psychological fact that we struggle to notice subtle changes. From the apocryphal frog in the pan who does not notice the water’s bubbles becoming larger to the many examples of “change blindness”, observing small shifts presents a significant cognitive challenge.

Climate change compounds the difficulty of this task. Many features of the environment evolve at the same time, obscuring any individual factor. Overall shifts take place amid seasonal cycles, adding a new dimension of complexity. And the underlying causal processes—from the SUV in Los Angeles to the melting ice caps in the Arctic—occur invisibly to the rice farmers in Bangladesh who bear the consequences.

A sensor I used to measure soil salinity levels. Most farmers lack access to this kind of technology. The core tension concerns the pace of global warming: how fast are changes taking place? The answer to this question is an inherently historical one, and critically hinges on whose history matters. From the perspective of the planet, the speed is astronomically fast. In geological time, the environmental shifts now rocking the tranquil rice fields of coastal Bangladesh occur at a thunderous gallop. But for the farmer, the changes often trickle along the space of human memory at an imperceptible drip.

These conflicting narratives encapsulate the challenge of learning about global warming—a critical step on the pathway to successful individual adaptation. Many harmful consequences of anthropogenic climate change are already irreversible, the damage of the recent decades too much and too fast for the earth. Yet for the most undeserving and vulnerable victims across developing countries, the changes can appear small and incremental, inhibiting households’ ability to react.

In on-going research, I examine these issues to try to better understand how people learn about climate change. Using recent developments in remote sensing technology, I build a new measure of flooding at a local level using satellites. Floods provide as-if random shocks to salinity depending on the timing and salt content of water. Combining this data with survey elicitations of people’s beliefs will allow me to understand how farmers form expectations and the types of signals that prompt reactions. By experimentally varying information and access to technology that aids farmers in the measurement of their fields, I will test how this learning shapes adaptation such as the planting of saline-tolerant seeds.  


Dev Patel
May 2022