Climate change is redrawing regional weather and climate patterns and risks

The impacts of climate change are becoming increasingly clear: more severe storms, changes to rainfall, prolonged and more extreme heatwaves, and rising sea levels to name a few. While the effects of a warming climate are felt globally, accurate information about regional impacts is critical to help communities prepare for the specific climate hazards they face.

Collins et al. present new insights into how climate change is affecting various regions around the globe, from the equator to the poles. Their Frontiers in Science lead article reveals the emerging patterns of severe weather events and environmental changes that pose significant risks to both human and natural systems, affecting everything from infrastructure and public health to economic stability and food security.

This explainer summarizes the article's main points, highlighting the crucial need for improved regional climate science to better understand regional impacts—a necessity for developing effective adaptation measures and policies to reduce risks and increase resilience to local climate change impacts.

What are the emerging signals of regional climate change?

Climate change signals refer to clear, measurable patterns indicating how Earth’s climate is changing due to human activities. Scientists detect these signals using observational data and advanced climate models.

Collins et al. present new results on regional climate change signals that we might expect to see this century, focusing on changes to:

• tropical rainfall, including monsoons and cyclones

• storms in midlatitude regions (the area between the subtropics and polar circles), particularly in the northern hemisphere

• precipitation in the Arctic and Antarctic and its associated effects

• El Niño events, which influence the climate differently in different regions

• extreme heat events.

How will climate change affect monsoons, cyclones, and tropical rainfall?

Monsoons, which are seasonal wind patterns bringing heavy rainfall to many regions, are crucial for agriculture and water supply. In the future, monsoons are expected to become more intense due to the combined effects of decreasing aerosol emissions and increasing greenhouse gas concentrations. This raises the risks of floods, landslides, and negative effects on crop yields, which could disrupt the lives and livelihoods of millions of people in affected regions—especially in northern hemisphere monsoon regions such as South Asia, East Asia, and West Africa.

Tropical cyclones also pose precipitation hazards, often accompanied by extreme winds and storm surges. As global temperatures rise, the intensity of tropical cyclones is projected to increase, putting areas such as the Indian and Bangladeshi coastlines at higher risk of extreme storm surges and flooding.

Rainfall in tropical rainforests, crucial for sustaining these biodiverse ecosystems, is projected to show varying changes depending on location. For example, more rain is expected to fall in New Guinea and the western Amazon while less precipitation is predicted in central and eastern Amazonia.

How will climate change affect midlatitude storms?

Climate models predict a potential strengthening of seasonal storm tracks into northwestern Europe. Storm tracks are pathways followed by storm systems, and stronger storm tracks mean more frequent and intense storms and cyclones. This shift increases the risk of extreme storms hitting land, which can bring high winds, heavy rainfall, and flooding. Such storms pose significant threats to infrastructure, homes, and communities, potentially causing widespread damage and disruption.

What will happen to precipitation at the poles?

In polar regions, the nature of precipitation is expected to change significantly—and decades earlier than previously anticipated. Due to rising temperatures, more precipitation will fall as rain rather than snow, especially in the Arctic. Rainfall on snow and ice can accelerate melting, which destabilizes ice sheets, ice shelves, and glaciers. This process contributes to sea-level rise, which threatens coastal areas worldwide by increasing the risk of flooding and erosion.

How will El Niño events change in the future?

El Niño Southern Oscillation (ENSO) events, which significantly impact global weather patterns, could become more frequent and severe within the next 20 years. This climate phenomenon is characterized by periodic warming of sea-surface temperatures in the central and eastern Pacific Ocean, contributing to floods, droughts, heatwaves, and wildfires in many parts of the world. More frequent and intense ENSO events mean greater and more widespread weather disruptions, affecting agriculture, water supply, and infrastructure in many regions.

What impact will heat extremes have on human health and agriculture?

Record-shattering heat extremes are projected to increase in both frequency and magnitude over the next century, with such climate change signals already being felt in Asia, West Africa, North America, and many parts of Europe. Humidity is also expected to rise, especially in tropical and subtropical areas.

The combination of high temperatures and humidity can cause heat stress and heat-related illnesses, especially among vulnerable populations such as the elderly, children, and those with pre-existing health conditions like asthma or chronic obstructive pulmonary disease. Increased heat can also reduce people’s ability to work outdoors, affecting sectors like construction and agriculture. Higher temperatures can additionally decrease crop yields by accelerating plant growth cycles, reducing maturation time, and increasing water demand—all of which could decrease food production and increase prices.

What are the next steps for mitigating and adapting to regional climate change impacts?

The regional signals of climate change described by Collins et al. highlight the increasing probability of climate hazards in different areas. The next step is to evaluate the vulnerability and exposure of populations and natural systems to these hazards. Such risk assessments are crucial for policymakers and communities to plan and implement effective adaptation and mitigation measures at a regional level—like improving infrastructure resilience, developing early-warning systems for extreme weather events, and altering work practices.

Collins et al. highlight that these efforts must be based on the most up-to-date information on current and future climate impacts. This requires further development of high-resolution models that represent “teleconnections” between regional changes to climate systems that can occur across great distances. However, the authors also emphasize that current uncertainties and knowledge gaps must not be a barrier to action: regional climate risks to economies, public health, and the environment can already be reduced via urgent adaptation and resilience measures and reductions in greenhouse gas emissions.