Unequivocal, unprecedented, irreversible, rapid and widespread. These are strong words used in the report of the Working Group I (WG1) of IPCC’s Sixth Assessment Report (AR6) released last August 9, 2021.
IPCC AR6 WG1: The Physical Science Basis of Climate Change
These are some of the major findings of the Working Group 1 report of the IPCC’s AR6.
Greenhouse Gas (GHG) emissions caused by human activities have significantly warmed the planet, leading to unprecedented and irreversible changes to the climate system. These findings are not new, but the Intergovernmental Panel on Climate Change (IPCC) authors now speak with certainty more than ever. The changes caused by global warming are rapid and widespread as was stipulated in the report.
As global surface temperature continues to rise, so does the extent of the changes in the climate system. This equates to more frequent and more intense extreme events such as hot extremes, marine heat waves and heavy precipitation, agricultural droughts, and sea ice and snow cover reductions.
The Philippines is one of the countries most affected by / vulnerable to the changing climate; the country has a lower coping capacity to the damaging effects of extreme weather events and may need more time to rebuild and recover (compared to more developed countries)
Proof of vulnerability: The Philippines ranked 4th among the countries most affected by extreme weather events in 2000-2019 (Long-term Global Climate Risk Index).
Causes of vulnerability: The Philippines’ climate vulnerability is mainly due to its geographic location and archipelagic structure.
The IPCC AR6 WG1 findings indicate that the impacts we are already experiencing from climate change will get worse. Increased temperatures will also exacerbate our current climate risks:
Sea Level Rise
As the ocean gets warmer, the water expands and increases in volume. This thermal expansion and the melting of sea ice and snow cover leads to sea level rise. Given the archipelagic structure of our country, sea level rise means more frequent tidal flooding, coastal inundation, destructive soil erosion, wetland flooding, aquifer and agricultural soil contamination with salt, and loss of habitats for fish, birds, and plants.
Relative sea level around Asia has increased faster than the global average, with coastal area loss and shoreline retreat. Regional-mean sea level will continue to rise (IPCC AR6 Regional Fact sheet).
In the case of the Philippines, the sea surface height of Manila Bay has already increased by 0.80 m from 1947 to 2012. It is projected to increase by half a meter more by mid-century and by up to 1.33 m by 2100 under the highest emissions scenario where no additional climate policy is implemented (SSP5-8.5).
More Intense Tropical Cyclones
Warmer sea surface generally provides more energy for storm development and thus favors more intense TCs. This means more powerful and even larger, thus more destructive tropical storms.
The increase in the amount of rainfall during heavy rainfall events is driven by an increase in atmospheric water vapour (IPCC AR6). Warmer atmosphere leads to more surface water evaporation over some regions. As warmer air rises, it is able to bring more moisture into the atmosphere. As air condenses eventually, this leads to more rain clouds and heavier rainfall over other locations. This could lead to flooding over some areas, and drought over other regions.
Compounded Extreme Events
Unprecedented compound extreme events, where multiple extreme events of either different or similar types occur simultaneously or in succession, may be more probable and severe. Heat wave/ extreme heat during drought increases the risk of forest fires and agricultural damages and losses. Sea level rise may induce higher storm surges caused by intense typhoons. Intensification of extreme events may lead to greater economic losses and fatalities.
Droughts and Heat Waves
Warmer air evaporates more water from reservoirs, crops and forests which leads to agricultural and ecological droughts.
Future heat waves are also expected to last longer and have higher temperatures, which can lead to agricultural droughts, decreased ocean productivity, and human health concerns.
Global temperatures reaching the 1.5 °C threshold implies more frequent severe droughts, heavy precipitation, flooding, heatwave, and typhoons to most of the world.
The Philippines is highly vulnerable to the severe impacts brought about by climate change. Below are some of the impacts that we can expect from our increased risks:
The IPCC AR6 WG1 was put together, reviewed and agreed upon by a team of 234 experts from 66 countries. Manila Observatory’s Faye Abigail Cruz is one of the contributing authors.
The report emphasizes that climate change is enhanced by human activities, particularly:
With humans contributing to climate change, IPCC also states that humans have the capability to stabilize the climate by reducing GHG emissions, which will be accomplished through net zero. Net zero emissions are achieved when anthropogenic emissions of greenhouse gases to the atmosphere are balanced by anthropogenic removals over a specified period.
More information on the impacts and recommended actions of climate change are available in the Philippine Climate Change Assessment Reports (PhilCCA).
The Philippines is one of the countries most vulnerable to the effects of climate change. Localizing global information is key to understanding how the changing climate affects the way of life of Filipinos. The PhilCCA Reports provide a clear and updated synthesis of the current state of scientific knowledge on climate change in the country, its impacts, vulnerabilities of various sectors, and adaptation and mitigation strategies, which can be instrumental in shaping policies to help build the resilience of Filipinos.
For the second cycle of the PhilCCA Reports, scientific literature published within the last five years will be synthesized by authors composed of the country’s top/ leading scientists, various stakeholders and relevant actors.
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