On this World Meteorological Day, WMO and ESCAP unpack the 2023 theme: Weather, Climate and Water across Generations – through a series of three opinion pieces focused on the Asia-Pacific region, each dedicated to answering the questions: What do weather, climate and water mean, how do they interact, and how are they changing? How do the changes in weather, climate and water impact our lives? What do we need to meet the needs of future generations concerning weather, climate and water?
Weather, climate, and water are crucial aspects of our environment and they have significant impacts on our daily lives.
Weather, climate and water are interconnected and influence each other in various ways.
Weather is the state of the atmosphere at a particular time and place and can vary from day to day or even from hour to hour. Weather patterns are influenced by various factors such as temperature, humidity, wind and precipitation.
Climate, on the other hand, refers to long-term weather patterns in a region, typically over 30 years or more.
Water is a vital resource that sustains life on Earth and has also been changing across generations. Water is a critical component of both weather and climate, as it plays a crucial role in the Earth's water cycle, which influences weather and climate patterns through evaporation and condensation.
Overall, weather, climate, and water are interconnected and know no national or political boundaries. Changes in one can impact others. Understanding these relationships is crucial for developing strategies to address the challenges of climate change and ensure sustainable management of water resources. In this blog, we will explore how weather, climate, and water have been changing across generations and the implications of these changes for future generations.
These elements have been changing across generations due to various factors such as human activities, natural processes, and global events.
How have weather, climate and water been changing?
Climate change refers to changes in the Earth's climate system that have been occurring over the past century or longer. Climate change has led to rising sea levels, increasing temperatures, and changes in precipitation patterns. These changes can be attributed to global warming, caused by the emission of greenhouse gases into the atmosphere, primarily from human activities.
Increase in extreme weather events and changes to the water cycle
Changes in the Earth's climate system can lead to changes in weather patterns, such as increased frequency and intensity of extreme weather events like droughts, floods, and heat waves. Climate changes also affect the amount and distribution of precipitation, which impacts water availability and quality – thus, affecting the timing and intensity of snowmelt, flood and drought events, impacting water availability for agriculture, energy production, and human consumption.
The Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) in 2022
shows that surface temperature has increased in the past century all over Asia, and rising temperatures have resulted in an increasing trend of growing season length. The number of hot days and warm nights continues to increase in Asia (high confidence), while cold days and nights are decreasing except in the southern part of Siberia.
Annual mean temperature anomalies (°C), 1900–2021, averaged over Asia, relative to the 1981–2010 average, for six global temperature data sets as indicated in the legend (Source: MetOffice, United Kingdom) in the State of Climate Report in Asia 2021.
According to the WMO State of Global Water Resources 2021, the first publication of the global state of water resources, freshwater storage is changing, our cryosphere (snow and ice) is increasingly vulnerable, and large areas of the globe recorded drier than normal conditions in 2021 - a year in which precipitation patterns were influenced by climate change and a La Niña event.
The changes to weather, climate and water can be clearly illustrated by viewing the increase in extreme climate events. The number of recorded disasters increased by a factor of five globally and in the region by a factor of four over the same 53-year period. The impacts of extreme weather events and a changing climate have far-reaching implications for ecosystems, human health, the economy, and society as a whole.
Number of Disasters in Asia and the Pacific by disaster type, 1970-2022 (Source: ESCAP calculations based on data from EM-DAT - The International Disaster Database. Jan 13, 2023)
Weather, climate, and water are interrelated and have been changing globally, particularly in the Asia-Pacific region. Three key facts of Weather, Climate and Water and how they are affected by climate change are described here:
On Weather. Climate change leads to more frequent and intense extreme weather events, such as floods, drought, tropical cyclones, heatwaves as well as sand and dust storms. These events significantly impact human health, ecosystems, and the economy. For example, heat waves can lead to heat-related illnesses and deaths, while droughts can cause crop failures and water shortages, floods can damage infrastructure and lead to the spread of waterborne diseases.
On Climate. Long-term weather patterns have been changing. This climate change includes rising global temperatures, changes in precipitation patterns, and sea level rise largely due to human activity. Evidence from the latest State of Global Climate 2022 has shown how the past eight years to be the eighth warmest on record, fuelled by ever-rising greenhouse gas concentrations and accumulated heat. Most glaciers in High-Mountain Asia and the South-West Pacific regions suffered from intense mass losses due to exceptionally warm and dry conditions in 2021, and the number of days of snow coverage was at a record low in the polar region of Asia.On water. Climate change is affecting the Earth's water cycle, leading to changes in the availability and quality of water. Changes in precipitation patterns are leading to more frequent and severe drought and flood events, which impact water availability for human consumption, agriculture, and energy production. Climate change also affects the sea-level rise, temperature and chemistry of oceans, leading to ocean acidification and impacts on marine ecosystems.
The impacts of climate change on weather, climate, and water are significant and wide-ranging. These impacts are likely to become more severe and more widespread in the coming years and decades, underscoring the urgent need for climate mitigations and adaptations.
WMO’s State of the Global Climate documents these changes, including global temperatures trends and their distribution around the globe; most recent findings on Green House Gases concentration, Ocean indicators, Cryosphere with a particular emphasis on Arctic and Antarctic sea ice, Greenland ice sheet and glaciers and snow cover; Stratospheric Ozone; analysis of major drivers of inter-annual climate variability during the year including the El Niño Southern Oscillation and other Ocean and Atmospheric indices; global precipitation distribution over land; extreme events including those related to tropical cyclones and wind storms; flooding, drought and extreme heat and cold events.
Since 2010 ESCAP has been developing the Asia-Pacific Disaster Report to deepen understanding of disaster risks and their implications on sustainable development in the Asia-Pacific region.
Since 2020, WMO and ESCAP have led the development of the State of Climate in Asia and the South-West Pacific – detailing the regional state of the climate in both regions, with their associated extreme events and implications for climate policy and actions.
Under an MoU since July 2003, ESCAP and WMO work together to strengthen the capacities of countries in the region through 8 priority areas (1) ESCAP/WMO Typhoon Committee, (2) WMO/ESCAP Panel on Tropical Cyclones, (3) Climate Risk and Early Warning System (CREWS) Initiative, (4) Regional Climate Outlook For a, (5) Sand and Dust Storm Warning Advisory and Assessment System, (6) Global Atmospheric Watch, (7) Asia Pacific Disaster Resilience Network, (8) Hydrological-related disaster risk management activities, including the Global Hydrological Status and Outlook System (HydroSOS).
(The authors would like to acknowledge Mr. Jun YU (WMO Regional Officer) for his contribution to the opinion pieces and for stewarding the cooperation between ESCAP and WMO)