climate change

Dec

2023

Heat extremes in the soil are underestimated, according to new study

Interesting study: “For a long time, little attention was paid to soil temperatures because, in contrast to near-surface air temperatures, there was hardly any reliable data available due to the significantly more complex measurement process. A research team led by the Helmholtz Center for Environmental Research (UFZ) has now established not only that ground and air temperatures can differ, but also that climate change has a much greater impact on the intensity and frequency of heat extremes in the ground than in the air. This is particularly the case in Central Europe, they write in the journal Nature Climate Change. ”

Heat extremes occur much faster in the ground than in the air
According to the station data, the intensity of heat extremes in Central Europe is increasing 0.7 degrees Celsius/decade faster in the ground than in the air.
The number of days with heat extremes is increasing twice as fast in the ground as in the air.
The decisive factor here is soil moisture, which plays an important thermal role in the exchange between air and soil temperatures.
If the temperature in the soil is higher than in the air, additional heat is released into the lower atmosphere – causing temperatures in the atmosphere to rise. “Soil temperature acts as a factor in the feedback loop between soil moisture and temperature and can thus intensify heat waves in certain regions”

https://www.ufz.de/index.php?de=36336&webc_pm=32/2023

Jul

2023

Is climate change exacerbated by photovoltaic systems?

Somewhat provocative question: however, if the statement is (somewhat) true:

“Regardless of how many greenhouse gas molecules are in the air, what determines the greenhouse gas effect is the amount of reradiation emanating from the earth.”

then we should think about the effect of warming from PV systems. In my talks, people often ask about the effect of PV systems – and they do, in fact, have the same effect as open ground or asphalt. They heat up (summer and winter; see picture above; source [1]) and thus radiate significantly increased long-wave radiation back into the atmosphere. This is the part that increases the greenhouse gas effect. Vegetation would normally convert most of the incident solar energy into latent energy, thus cooling the environment and bringing energy from the layers near the ground into the higher atmosphere, where a part can diffuse into space upon condensation. Completely different conversion of solar energy and corresponding consequences.

[1] https://www.energiedetektiv.com/fileadmin/user_upload/documents/PDF/Klimawandel_durch_Klimaschutz_E.pdf

Jul

2023

The ocean is turning green. Yes, it’s climate change

Not good news: More than half of the world’s oceans have changed colors in the past 20 years, becoming more green than blue. The culprit? Climate change. In a study, published Wednesday in Nature, decades worth of research showed 56 percent of the world’s oceans experienced color change between 2002 to 2022.

“The study’s authors say that natural instances, like seasonal or yearly variations to phytoplankton blooms, don’t explain the oceans’ shift in color, and don’t account for the change. Instead, researchers say the greening might better be explained by carbon dioxide absorption by plankton and algae communities and could signal an even more serious problem: Oceans absorb nearly 25 percent* of the world’s carbon emissions and may not be able to absorb more in the future.”

May

2023

The ocean is hotter than ever

Wow, not so good news… Oceans are heating up, more and more. The ocean absorbs about 90% of the extra heat in the climate system resulting from global warming. But because it takes more energy to heat water than air, the surface water temperature is rising more slowly than the surface air temperature is.

I developed a few years ago some graphics (source 1, source 2) on this, which shows the trend too:

Incredible, if we imagine that heat would have solely gone into the atmosphere – where would we be now?

May

2023

What is warming the climate – CO2 or forest loss?

As the only accepted narrative on global warming is the one on CO2 (and other GHG), I wonder since a couple of years what the influence disappearing vegetation, especially deforestation, in conjunction with bare soils, and its disruptions of the small water cycle has on the changing climate. Vegetation means transpiration, which leads to a cooling effect within the ground layer (we need that!), and the transfer of that stored energy in the water vapour into higher parts of the atmosphere (which is beneficial). Here, when released, some of it (some people say up to half) disappears into outer space (which is good for climate cooling). The condensation means clouds are being created, which reflect incoming radiation (another positive effect). Clouds mean it can bring rain (which is more and more missing in its usual regularity around the world). Vegetation actually emit biogenic aerosols, which help to create these clouds at lower atmospheric levels, creating more rapid and more regular rain (another important benefit). And there is more to it (see links below).

Now, a funny (?) thing:

When looking on CO2 concentration and global temperature anomaly, we see a strong correlation:

However, the interesting thing is, that we see the same correlation between the loss of primary (and naturally regenerated) forests (which are the most important drivers of the small water cycle) and the temperature anomaly:

This is not to say that the CO2-narrative is wrong. I am convinced that we must urgently stop emissions and try to store emitted CO2 in soils and vegetation. But I wonder what influence the disappearance of natural forests, the increasing amount of bare soil and surfaces (asphalt, beton, buildings), the loss of water retention and storing capacities in the landscape and the according changes in the energy redistribution/balance/transport has on climate change.

More and more research shows that this is not negligible (see articles in my blog), but could even prove to be a major factor.

Interesting additional links:

my UNEP paper “Working with plants, soils and water to cool the climate and rehydrate Earth’s landscapes“
my presentation “Planting water“
the Climate Landscapes Conference

Aug

2022

Does Climate Change cause Extreme Weather?

Interesting explanation on the why/how/if of extreme weather attribution maths: In the past two years or so we have seen many headlines about extreme weather events: floods, droughts, heat waves, hurricanes. In some cases, climate scientists claim they can “attribute” those extreme weather events to climate change. But what exactly does that mean? How does one calculate this? And how reliable are those estimates? This video is a brief intro into the young research area of extreme event attribution.

Apr

2022

Land use and climate change : an interview with Millan Millan

Meteorologist Millan Millan’s research work discovered that rain was disappearing because land use was affecting evapotranspiration rates. In this podcast he talks about what we need to do to restore rains and ecosystems.