Jakarta, CNBC Indonesia \u2014 Volcanic eruptions are not only geological\ndisasters, but can also affect weather and even climate.<\/p>\n
The impact of volcanic eruptions is currently drawing attention amid\nthe eruption of Mount Anak Krakatau. The volcano, located in the Sunda\nStrait, has been erupting continuously since Friday (4\/9\/2026). Volcanic\nash has spread as far as Jakarta, Banten, and several areas in Java and\nSumatra.<\/p>\n
The event has forced eight airports to halt operations, disrupting\nmore than 1,500 flights and some 170,000 passengers. The ash column was\neven detected reaching around 50,000 feet, or 15 kilometres, on the\nSumatran side.<\/p>\n
But can eruptions like this also change the climate?<\/p>\n
Can Volcanic Eruptions Change the Weather?<\/p>\n
In the short term, volcanic eruptions can affect atmospheric\nconditions around the affected area. Volcanic ash can reduce visibility\nand the sunlight reaching the surface, whilst volcanic particles and\ngases can also interact with clouds and local weather conditions.<\/p>\n
However, influencing the global climate requires eruptions on a far\nlarger scale.<\/p>\n
According to the National Oceanic and Atmospheric Administration\n(NOAA), the eruptions most capable of affecting climate are explosive\nones that propel large quantities of material and gas into the\nstratosphere, the atmospheric layer above most weather systems.<\/p>\n
This is where the distinction between volcanic ash and sulphur gas\nbecomes important.<\/p>\n
The US Geological Survey (USGS) explains that most ash reaching the\nstratosphere falls back within days to weeks, so its climate impact is\nrelatively small. By contrast, sulphur dioxide, or SO\u2082, can transform\ninto sulphate aerosols that persist far longer.<\/p>\n
How Can a Volcanic Eruption Actually Cool the Earth?<\/p>\n
When SO\u2082 reaches the stratosphere, the gas reacts with water vapour\nand forms sulphate aerosols \u2014 tiny droplets of sulphuric acid.<\/p>\n
These particles reflect and scatter part of the sun\u2019s radiation back\ninto space, reducing the energy reaching the Earth\u2019s surface and causing\ntemperatures to fall temporarily.<\/p>\n
This effect can last from months to several years, because sulphate\naerosols in the stratosphere are not easily washed away by rain and can\nspread widely following atmospheric circulation.<\/p>\n
NOAA explains that the cooling effect from reflected sunlight is\ngreater than the warming effect caused by aerosols trapping some of the\nEarth\u2019s infrared radiation.<\/p>\n
These changes can also affect atmospheric circulation, wind patterns,\nand rainfall, although the impacts vary from region to region.<\/p>\n
In other words, major eruptions can indeed influence the climate, but\nthe effect is generally temporary. This differs from warming caused by\ngreenhouse gases from human activity, which continues to accumulate as\nlong as emissions persist.<\/p>\n
Volcanoes Also Produce Greenhouse Gases (GHG)<\/p>\n
Volcanoes do emit carbon dioxide (CO\u2082), one of the main greenhouse\ngases driving global warming.<\/p>\n
However, the scale is far smaller than emissions from human\nactivity.<\/p>\n
The USGS estimates that all of the world\u2019s volcanoes, on land and\nunderwater, release about 0.13\u20130.44 gigatonnes of CO\u2082 per year, with a\ncentral estimate of around 0.26 gigatonnes per year.<\/p>\n
By comparison, data from the International Energy Agency (IEA) shows\nthat global CO\u2082 emissions from energy combustion and industrial\nprocesses have continued to rise over the long term, reaching around 38\ngigatonnes in 2025.<\/p>\n
This means CO\u2082 emissions from energy combustion and industrial\nprocesses are currently several hundred times larger than the estimated\nemissions of all the world\u2019s volcanoes combined. So although volcanic\neruptions can affect the climate in the short term through sulphate\naerosols, the rise in CO\u2082 concentrations and long-term global warming is\nstill driven overwhelmingly by human activity.<\/p>\n
Major Examples: Pinatubo and Tambora<\/p>\n
Large eruptions have proven capable of temporarily lowering global\ntemperatures. The 1991 eruption of Mount Pinatubo in the Philippines\ninjected large quantities of sulphur into the stratosphere and caused\nmeasurable global cooling for several years.<\/p>\n
The 1815 eruption of Mount Tambora contributed to the phenomenon\nknown as the \u2018Year Without a Summer\u2019 in 1816. The shifts in temperature\nand weather patterns disrupted growing seasons and triggered crop\nfailures in several parts of the world.<\/p>\n
So What About Anak Krakatau Now?<\/p>\n
Although Anak Krakatau\u2019s ash has this time reached heights of around\n15 kilometres, there is no evidence yet that the current eruption is\nlarge enough to produce a climate-cooling effect like Pinatubo or\nTambora.<\/p>\n
The height of the eruption column alone is also not enough to\ndetermine climate impact. More important factors are how much SO\u2082\nactually enters and persists in the stratosphere, and how widely the\nresulting aerosols subsequently spread. The USGS and NOAA stress that\nmajor climate effects mainly arise when explosive eruptions inject very\nlarge quantities of sulphur into the stratosphere.<\/p>\n
So for Indonesia today, the most tangible impact is in fact local and\neconomic, rather than a change in the global climate.<\/p>\n
On the other hand, volcanic cooling is not good news for climate\nchange either. The cooling is only temporary and does not remove the CO\u2082\nthat has already accumulated in the atmosphere. When the sulphate\naerosols eventually disappear, their cooling influence vanishes with\nthem, whilst warming from human emissions remains.<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/volcanic-eruptions-can-actually-cool-the-earth-how-1788774720", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }