Premature hatching associated with climate change may lead to depletion of fish stocks

Tiistai 15.10.2024 klo 17.47 - Mikko Nikinmaa

Cowan et al. reviewed premature hatching of fish embryos in climate change scenario in Global Change Biology (DOI: 10.1111/gcb.17488). Virtually all anthropogenic changes in aquatic environment trigger premature hatching: temperature increase, hypoxia, acidification and increase of water carbon dioxide content, presence of pathogens, metal pollution and organic pollutants.

Simplified, hatching starts to occur, when the oxygenation level of the embryo decreases below a setpoint. This triggers the secretion of choriolytic enzymes, which enables the embryo to break the egg surface and become a fry. In the case of increased temperature, small increases can be tolerated, as, although temperature increase increases the oxygen consumption of the embryo, it also speeds up development and thus the embryo is adequately developed when the hatching program sets on earlier than at lower temperatures. However, too fast and pronounced increase in temperature leads to a decrease in embryonal oxygen level, which triggers hatching, before the embryo is adequately developed. In such a case, mortality at hatch and during the early life of the fry is increased. In hypoxic conditions, the oxygen level triggering hatching is often reached before the embryo is adequately developed for normal life, causing increased egg and fry mortality. Several pollutants and infections also affect the oxygen consumption of the embryo in such a way that development at hatch is not optimal for successful later life.

Although optimal oxygen level of the embryo at hatch is the most important factor affecting fry recruitment, virtually no fisheries estimations/predictions take that into account. Stock recruitment is still based mainly on catch statistics, although such metrics cannot take into account anything that affects egg and fry development. Yet, early development of fish is the major driver of future fish stocks.

The 2024 state of the climate report: Perilous times on planet Earth

Keskiviikko 9.10.2024 klo 14.08 - Mikko Nikinmaa

William J. Ripple et al. have published the above report in Bioscience , (https://doi.org/10.1093/biosci/biae087). I place its conclusions below.

Despite six IPCC reports, 28 COP meetings, hundreds of other reports, and tens of thousands of scientific papers, the world has made only very minor headway on climate change, in part because of stiff resistance from those benefiting financially from the current fossil-fuel based system. We are currently going in the wrong direction, and our increasing fossil fuel consumption and rising greenhouse gas emissions are driving us toward a climate catastrophe. We fear the danger of climate breakdown. The evidence we observe is both alarming and undeniable, but it is this very shock that drives us to action. We recognize the profound urgency of addressing this global challenge, especially the horrific outlook for the world's poor. We feel the courage and determination to seek transformative science-based solutions across all aspects of society. Our goal is to provide clear, evidence-based insights that inspire informed and bold responses from citizens to researchers and world leaders.

Rapidly phasing down fossil fuel use should be a top priority. This might be accomplished partly through a sufficiently high global carbon price that could restrain emissions by the wealthy while potentially providing funding for much-needed climate mitigation and adaptation programs. In addition, pricing and reducing methane emissions is critical for effectively mitigating climate change. Methane is a potent greenhouse gas, and unlike carbon dioxide, which persists in the atmosphere for centuries, methane has a relatively short atmospheric lifetime, making reductions impactful in the short term (Shindell et al. 2024). Drastically cutting methane emissions can slow the near-term rate of global warming, helping to avoid tipping points and extreme climate impacts.

In a world with finite resources, unlimited growth is a perilous illusion. We need bold, transformative change: drastically reducing overconsumption and waste, especially by the affluent, stabilizing and gradually reducing the human population through empowering education and rights for girls and women, reforming food production systems to support more plant-based eating, and adopting an ecological and post-growth economics framework that ensures social justice (Table S4). Climate change instruction should be integrated into secondary and higher education core curriculums worldwide to raise awareness, improve climate literacy, and empower learners to take action. We also need more immediate efforts to protect, restore, or rewild ecosystems.

The surge in yearly climate disasters shows we are in a major crisis with worse to come if we continue with business as usual. Today, more than ever, our actions matter for the stable climate system that has supported us for thousands of years. Humanity's future depends on our creativity, moral fiber, and perseverance. We must urgently reduce ecological overshoot and pursue immediate large-scale climate change mitigation and adaptation to limit near-term damage. Only through decisive action can we safeguard the natural world, avert profound human suffering, and ensure that future generations inherit the livable world they deserve. The future of humanity hangs in the balance.

Cooling Towns Down: Green Areas around Cities

Lauantai 27.7.2024 klo 15.24 - Mikko Nikinmaa

Already in 1960’s Lovin’ Spoonful sang “…hot town, summer in the city.” Indeed, towns are much hotter than the countryside around. Asphalt and concrete, streets and buildings without trees and green areas form heat domes where temperatures increase whenever sun shines. Since an increasing percentage of people live in cities, increasing temperatures have become a major health issue with climate change.

A within town solution to decrease temperatures in the cities is to plant trees to line streets and include a lot of parks in the areas. The effects of trees on the street temperatures has been estimated, and the difference between “bare” and tree-lined streets can be 5-10 degrees centigrade. Another way of decreasing city temperature is to use reflective materials/paints on rooftops. Any colours used should be light to reflect as much solar radiation as possible.

Although the above ways can decrease city temperatures to some degree, the presence of many streets and buildings necessarily increases city temperatures above those of woodlands. However, if a city is surrounded by woodlands, the following occurs:

1. Since the city temperature increases, the warm air tends to rise upwards generating a low-pressure zone in the city.
2. The cooler air flows from the surrounding woodlands to the city, whereby the measured temperature decreases and, further, the moving air, i.e. wind, makes the temperature feel more tolerable than without wind.

The influence of green areas surrounding towns on their temperatures has been reported by Yang et al in Nature Cities (2024; https://doi.org/10.1038/s44284-024-00091-z).

An underexplored source of climate change information: scientific studies on temperature effects in animals between 1970 and 1990

Keskiviikko 5.6.2024 klo 20.01 - Mikko Nikinmaa

The major problems of climate change and eutrophication caused to aquatic environments are caused by increased temperature and reduction of oxygen in water. Both problems have started getting public attention from 2000 onwards. However, scientists were interested in these questions already in 1960’s and 1970’s, generating a lot of information that could be, and to some extent has been, used in order to understand which aspects of animal life can be adjusted in climate change scenarios.

I am proud to say that I started working on temperature and hypoxia acclimation among the pioneers. For example, my thesis RESPIRATORY ADJUSTMENTS OF RAINBOW TROUT (Salmo gairdneri RICHARDSON) TO CHANGES IN ENVIRONMENTAL TEMPERATURE AND OXYGEN AVAILABILITY was published in 1981, long before such work became fashionable.  Being among the dinosaurs one unfortunately notices that much of the information from 40-50 years ago is not known to many of today’s researchers, leading to unnecessary waste of resources and occasional inventing the wheel again.

Both temperature increase and decreased oxygen levels cause mainly respiratory problems, as with increasing temperature the oxygen consumption of poikilotherms such as fish increases. At high temperatures the efficiency of circulatory system (including heart function) cannot increase adequately to allow for required oxygen consumption. Increased temperature as such also causes a reduction in the dissolved oxygen level, causing the likelihood of hypoxic or even anoxic waters to increase. With reduced oxygen levels, gill function, properties of oxygen-transporting haemoglobin and tissue oxygen consumption become decisive for tolerance. Fishes, which comprise about a half of all vertebrate species, have invaded all aquatic environments from the cold arctic waters to tropical anoxic ponds. Because of this, it is not likely that temperature increase or hypoxia would result in completely fishless aquatic environments in today’s temperate or cold latitudes in the long run. However, individual species may disappear completely, and often the species unable to adapt are today’s commercially important species like cod and salmonids. Furthermore, it takes time for new species to immigrate to areas, where earlier fish species have disappeared, leaving the areas virtually fishless for some time. Surprisingly, tropical areas are in the biggest threat of total fish extinction for two reasons: first, the temperature tolerance of tropical fish is limited: being stenothermal they cannot survive even if temperature increases only a little. Second, no species from an even hotter environment can migrate to the areas left fishless, because such areas do not exist.

It would be useful for today’s researchers to spend more time reading what has been written about the adaptations of fish to changes in temperature and oxygen availability in the past. Also, it would be important to take into account the speed and magnitude of the changes in the natural environment; often the experimental work is carried out in much shorter time scale and much larger environmental changes that are likely to happen in nature. Despite this, the results are usually interpreted as if they gave reliable information of the success of fish in climate change scenarios.

Another recordhot month - February 2024

Torstai 14.3.2024 klo 18.17 - Mikko Nikinmaa

February was 1.77^oC warmer globally than the preindustrial average for the month. It is now the ninth month in a row with highest measured average global temperature. For me this can hardly be happening without climate change contribution. Yet, US Republican presidential candidate Donald Trump says “drill, drill, drill” and right wing populists throughout Europe ask for lower petrol prices. No doubt that they will saying that there is no climate change if and when the temperature decreases next year. A decrease in global average monthly temperatures is expected to happen next year when the cooler La Nina weather pattern will replace the hot El Nino weather pattern in Pacific Ocean.

The February temperature was particularly high in Europe, 3.3^oC above preindustrial average. Anybody with alpine skiing as a hobby certainly noticed this. Most ski resorts had only snow in some of the slopes, and offpist was out of the question because of the lack of snow.

Fossil fuel use must be stopped

Torstai 9.11.2023 klo 19.42 - Mikko Nikinmaa

Use of fossil fuels is still increasing, although there cannot be any doubt about climate change. This year (2023) is going to be the hottest one globally in the recorded history, and unnormal weather – heavy rain, drought, storms etc. – has occurred throughout the world. In spite of the increasing cost of repairing infrastructure after foul weather and wildfires, which have also increased drastically, the conservative parties throughout the world maintain that one cannot go away from oil-based economy: according to them the continued use of fossil fuels is the only way to avoid going deeper in debt and thus required for the sake of future generations.

However, it is quite clear that oil, gas and coal burning are causing the climate-related problems. It has recently also become clear that climate change occurs more rapidly than has earlier been predicted. We are already approaching many tipping points, which cause problems for future generations’ lives. And whereas monetary loans can be left unpaid, changes in the physical environment cannot just be written off. Loan is just an agreement in which the lender gives money to the loaner taking interest, i.e., profit on the amount given. Since loan market functions, there must be funds somewhere enabling the loan-based economy. That is completely different from the physical condition of the world. There is no planet B which we could start to use once we have spoiled the Earth.

The conservative thinking that we can continue the use of fossil fuels to avoid getting deeper in debt is fallacy and not sustainable. We should get our priorities right: first, we must have healthy environment. If that cannot be done without increasing debt, we must loan more money.

Fish in high-flow zone of rivers may be the first victims of climate change

Maanantai 25.9.2023 klo 18.56 - Mikko Nikinmaa

Fish living in high-flow areas of rivers have chosen (or evolved in) that habitat, because they need a lot of oxygen for their high activity. Flowing water becomes well oxygenated, as it is continuously exposed to air. However, the amount of oxygen taken up by water decreases with increasing temperature, simultaneously as poikilothermic fish need more of it, as temperature increase speeds up their metabolism.

If temperature increases enough, fish heart cannot pump enough oxygenated blood to sustain metabolism. This we have clearly shown in our article Anttila et al, Comp Physiol Biochem A 275, 111340 (2023). Although the study was done on seabass, the principle holds also for river fish. The amount of oxygen initially reaching the gills, where it is taken up, further decreases the maximal temperature the fish can tolerate.

Zhi et al (Nature Climate Change 2023;  https://doi.org/10.1038/s41558-023-01793-3) have shown that the oxygen level in rivers throughout Europe and United States has decreased for the past forty years. While increased temperature was the main driver, the oxygen level decreased more than expected because of temperature increase. It is possible that the general eutrophication with increased oxygen consumption.

Regardless, associated with the physiological response to increased temperature of fish, the temperature-caused decrease in maximal amount of oxygen the water holds, can cause extinction of salmonids living in the fast-flowing head streams.

Possible effects of climate change to Central and Northern Europe

Keskiviikko 2.8.2023 klo 19.25 - Mikko Nikinmaa

We have been taught at school how the temperature in Central and Northern Europe is much higher than at similar latitudes elsewhere. The reason for this has been Gulf Stream, which flows northeast from the Gulf of Mexico to the Arctic, North of Norway. The stream moves a lot of heat from tropics to high latitudes. Finally the water cools and sinks to the bottom of the ocean and the cold water flows back south in southwest-directed cold streams. An important part of the dynamic water flow is that the Gulf Stream water sinks to ocean bottom, because that generates the driving force for water circulation. In the absence of water circulation, Central and Northern Europe would be much colder than presently, especially in winter. Gulf Stream water sinks, because when its temperature decreases to four degrees centigrade, the density of water is higher than the water below, which has a lower temperature. The density of water depends also on its salinity, the higher the salinity, the higher the density. Earlier on this has also contributed to the water circulation. The surface water flowing in Gulf stream from tropical areas has traditionally had higher salinity than the bottom water of the Arctic Sea.

 Climate change is now threatening to change this warmth-bringing ocean circulation. The melting of Greenland glaciers but also the sea ice of the arctic causes a significant decrease in the density of surface water in the Arctic Sea. As a result, the sinking of Gulf Stream water from the surface to the bottom can be markedly reduced. This decreases the driving force for ocean circulation, and Gulf Stream may stop flowing altogether. The result for Central and North European climate would be that we experience Siberia-like weather patterns. An additional problem associated with presently ongoing freshwater addition is that the global temperature rise observed already seems to be adequate to cause continuing glacier melting in Greenland. This suggests that even if we are able to stop temperature increase to 1.5 degrees centigrade, the weakening of Gulf Stream may occur. There is no way to know, when we reach the tipping point.

So, if climate deniers tell you after three cold winters that clearly there is no climate change, as we have cold winters, you can answer them: “On the contrary, this shows that climate change has reached another tipping point. The heat transfer from tropics to the north in the form of Gulf Stream has stopped.” The real problem with this, and the weather patterns in general, is that what has happened and is happening is increased unpredictability. That is probably the biggest problem with climate change.

Heart function and individual variability play major roles in temperature tolerance of fish

Maanantai 14.11.2022 klo 14.42 - Mikko Nikinmaa

Climate change has major effects on fish, especially fish in lakes, since the whole water body can warm up as a result of long-lasting heat waves. Because of the uniform temperature regardless of the depth, fish cannot seek colder temperatures near the bottom. As a consequence, massive fish mortalities occur in shallow lakes of temperate zone every summer nowadays.

The reasons, why fish die as a result of increased temperature can only be understood by studying the functional changes occurring as a result of temperature elevation. Thus, physiological studies should be in the centre of climate change studies. If the reasons for vulnerability to increased temperature are known, it can also be estimated, which measurable responses predict fish mortalities. This as a background, and recognizing that individual variability of fish determines why some die and others remain living, we studied how fish tolerant and intolerant to high temperatures differed from each other. The results of the extensive studies are reported by Anttila et al in Comparative Biochemistry and Physiology (//doi.org/10.1016/j.cbpa.2022.111340).

Our results show that for a given age group, heart function is decisive in determining temperature tolerance. The efficiency of heart is markedly different in different individuals, whereby marked individual variability in temperature tolerance occurs. Thus, in predicting the effects of climate change on fish populations, we should not restrict our analysis to the mean response but also to the variability observed. In future it must be evaluated to which extent the thermal tolerance and its variability are heritable, as this will have significant impact on the vulnerability of species to global warming.

Fish kill in Oder river - blame the climate change

Maanantai 26.9.2022 klo 15.11 - Mikko Nikinmaa

The temperature measured in Oder river was exceptionally high, when the mass mortality of fish occurred. Although other factors certainly also had a role, this was the primary reason for the fish kills. This is because the difference between the tolerated upper temperature and the temperature causing death is small regardless of fish species. There are cold water species, species which have very small temperature range where they live, warm water species, and species which live in a wide range of temperatures. However, regardless of their temperature preference or tolerance, when fish are close to their upper critical temperature, the difference between tolerable and lethal temperature is small.

Thus, Oder river fish kill is something we are going to see with increasing frequency, if urgent actions are not carried out to combat climate change. They cannot wait until energy price comes down. And, actually the huge increase in energy price as a result of Russian energy war shows that Europe has been too slow in green conversion. If it had been rapid enough, the stop of Russian gas export to Europe would not have affected energy price at all. Now we are suffering from the slow replacement of fossil fuels by green energy. The Oder fish kill shows that we must tolerate the high energy price and speed up the transfer to green energy.

The thermal tolerance of fish is not increased by 40-45 years of exposure to increased temperature

Sunnuntai 25.9.2022 klo 18.42 - Mikko Nikinmaa

The waters in the vicinity of nuclear power plants give a possibility to investigate how increased temperature affects fish populations. Nuclear power plants use ambient water to cool down the units where energy is produced. The cooling water is returned to the environment. As a consequence the water in the vicinity of the power plant is 2-5^oC higher than in the environment generally. In Finland, nuclear power has been produced 40-45 years, so organisms have experienced the increased temperature for that period of time. Both the temperature increase and the duration of exposure are similar to what can be expected to occur as a result of climate change.

In her Ph.D. thesis, which is defended on September 30, 2022, Giovanna Mottola used this natural exposure to evaluate, if the 40-45-year exposure was able to improve the thermal tolerance of stickleback. The results indicate first, that regardless of the previous exposure history, a short heat wave increases the highest temperature tolerated acutely, and second, that previous history of living in the high temperature of the vicinity of nuclear power plant does not affect the temperature tolerance as compared to non-exposed fish. This means that fish living at an increased temperature are closer to the tolerance limit than fish living in cooler temperatures, and if a heat wave occurs, are consequently more likely to succumb. Although the studies are only on one species, similar results have been observed with the couple of other species so far studied. This suggests that the upper thermal tolerance of a given species is fixed and cannot be evolutionary increased within the time window available in climate change scenarios.

If one then considers on the basis of the natural laboratory data the ecological status of fish populations in the climate change scenarios, it appears likely that marked disappearance of fish occurs, before the migration of more temperature-tolerant, southern fish occurs. This will be true because of the time constraints of movement. Also, coastal fish are not likely to cross open water areas, so in their case the northward migration of southern populations is further slowed down.

Extreme heat in Europe - a new normal together with cold spells in winter, if climate change is not stopped

Tiistai 20.9.2022 klo 11.29 - Mikko Nikinmaa

The climate models predict that the circulation of warm water towards north and cold water to the south can radically decrease in near future. This is mainly the result of the melting of Greenland ice sheath, which liberates a lot of fresh water to the Arctic Ocean/North Atlantic. Because of this, the surface water becomes less dense than earlier and will not sink in the water column. The downward movement of surface water is the main driver of northward current of warm water in Gulf Stream. Since Gulf Stream keeps the European climate temperate increasing especially winter temperatures, its weakening may change the climate towards Siberian-like.

Other major effectors of European climate are the jet streams at high altitude. Their movements to a large extent determine the movement and stability of low and high pressure zones, and depending of the location of the zones if tropical or arctic air is moving towards Europe. The jet stream has recently started to split more often than earlier, and between the split any weather pattern becomes more stationary that earlier. Although there is no conclusive evidence that the increased splitting of jet stream would be caused by climate change, it has only started to occur recently, more or less at the same time as the global average temperature has increased more than one degree centigrade.

The two factors, weakened Gulf stream and jet stream function, predict that Europe can expect extended heat spells in summer and cold winters. The cold winter weather may occur even though the global temperature increases markedly. So, the truth value of the following is zero. “Look, it is cold now, there is no climate change”, as climate sceptics certainly shall say. But scorching heat in future summers becomes even worse than in 2022   

Why do some people still say that there is no climate change?

Tiistai 16.8.2022 klo 11.58 - Mikko Nikinmaa

I just add a picture of Central European river (The river is supposed to run, where you only see stones). After seeing photos like that, it is very difficult to understand why the same people who worry so much about leaving debt to future generations, are climate change deniers. (photo by Tobi Kellner) 

Heat Tolerance of Some Animals Is Already Exceeded

Tiistai 19.4.2022 klo 20.22 - Mikko Nikinmaa

Among animals, humans are probably among the best in adapting to hot and arid environments. There are several reasons for this. First, we have lost the fur coat almost completely – thus the name “naked ape”. This maximizes the heat loss. Second, humans are able to use evaporative cooling better than virtually any animal. We have more sweat glands per unit area than other mammals, and the glands are of the eccrine type, whereas the glands of most other mammals are of apocrine type. Eccrine glands are capable of secreting sweat of low salinity for a long period of time. In contrast, the sweat form apocrine glands is of higher salinity, and the secretion capacity is smaller. Many mammals such as cats and dogs have limited number of sweat glands: they are completely absent in bats. Also in birds evaporative water loss is a major mechanism of cooling. This is often done by panting and in some species by gular vibration. The physiology of heat tolerance in small endotherms has been reviewed by McKechnie and Wolf in Physiology 34:302-313 (2019).

The problem with evaporative cooling is that it requires water, which is very scarce in arid environments. Thus, even in species such as humans, which have efficient evaporative heat loss, the lack of water may cause mortalities. As most hot areas also become drier, this is a major problem with climate change. That the heat-related problems have already become serious ones even to humans is given by the estimated increase in heat-related deaths, which has increased 20-fold in 20 years after 1990’s. For humans the mortality is small as compared to bats in Australia and in South Africa. As bats don’t have sweat glands, their tolerance of increased temperature is very weak. So heat waves have caused many bats to literally drop dead from the trees they have lived in. It is estimated that for one particular species 1/3 of the population has died because of the heat. In Australia and South Africa also mass mortalities of birds have occurred because of heat waves. I bet that similar heat-induced mass mortalities have taken place also in other hot, arid areas, but there have not been scientific reports about them. Also birds appear to have weaker tolerance of increased temperatures than mammals.

Any temperature increase now will put an increasing number of species to knife’s edge regarding their survival. Bats and birds serve as first indicators of intolerable heat. So, canary birds were used in coal mines as warning signs. Now birds indicate that coal use must be stopped. It is appropriate that the first mass mortalities of animals occurred in Australia as the country is the biggest coal exporter in the world.

Physiological studies should be in the centre of climate change biology

Tiistai 12.4.2022 klo 15.49 - Mikko Nikinmaa

Climate change, and other environmental changes, affect the functions of organisms. The changes in populations and ecosystems follow these functional changes. If the functions of some organisms are not disturbed, the environmental change does not affect the ecosystem, if immigration and emigration can be accounted for.

These simple facts indicate that functional studies, i.e., physiology, should be in the centre of environmental biology. Indeed, a stone could have exactly the same molecules as an organism, but without functions it would still be a stone. However, physiological studies are marginalized in climate change research and environmental biology – there are less than 1/10^th of published physiological articles as compared to ecological articles within environmental biology. Furthermore, studies on animals account for less than 1/3^rd of the physiological studies.

In short, one carries out extensive ecological surveys and population genetic studies and observes that something has happened. This is the major problem with the research, it shows what has already occurred, but fails to evaluate why and how. With climate change research it is obvious that temperature increase plays a role, but only physiological studies can clarify, what the affected pathways are. Also, physiological investigations can answer in real time, if a disturbance is adequate to cause a perturbation in populations and ecosystems.

Climate change research as well as other environmental biology should be predictive. This requires that physiology becomes a central, not a marginal discipline. Studies require intensive, time-demanding work, which is often technically quite demanding. Because of this, the number of scientists working on physiological questions should be drastically increased. Only this makes it possible to turn environmental and climate change biology to predictive science, which is required to combat environmental problems.

IPCC Report: an immense amount of information that climate change already affects the earth

Tiistai 1.3.2022 klo 19.06 - Mikko Nikinmaa

Another IPCC report has become available yesterday (February 28). They keep becoming larger, the full report now has 3685 pages. Its main findings are summarized in 35-page summary for policymakers. I am not going through the impressive amount of information, it can all be read at https://report.ipcc.ch/ar6wg2/index.html, but giving my musings about why this information is not accepted by almost a half of the people in industrialized countries. The publication of the IPCC report has been relegated to a secondary news item, because of the attack of Putin’s Russia to Ukraine, but the two have surprising links.

Russia’s main income is from oil and natural gas. Since the world is trying to diminish the use of fossil fuels, Russia’s incomes will be diminishing in future. Furthermore, since quite a few buildings have been built on permafrost, which is melting, there is a huge need for investments on new grounding of them. Together these facts mean that Putin saw his window of opportunity to restore the might of Russian empire to be now or never. I suppose he imagined that Ukraine could be easily conquered and puppet government installed there. That did not happen. He also supposed that Europe and NATO would be split. That did not happen, either. Rather, the unity of the Western World has increased, and resulted in so massive sanctions that Russian economy is reeling. This increases the economic problems that I alluded to above.

But, going to the climate deniers’ arguments. They are stating that government should decrease the price of fossil fuels and slow down the replacement of fossil fuels by carbon-free energy sources. Since already now the temperature increase is causing irreversible problems, the delay on the stop of fossil fuel use would cause increased climate-related problems. Besides, that would play in the hands of Putin regime, as it would increase the sales of natural gas and oil from Russia. In Finland, an argument is presented that one should continue the use of peat in the name of national fuel/energy security. However, peat can be equated to fossil fuels in the time range of climate change. Furthermore, the national energy production security can be obtained by wind power, because no foreign nation can stop the wind. Third, the climate deniers always say that there have always been changes in earth’s climate. This is naturally true, but the sheer speed of the change is unprecedent. In addition, predictable weather has actually enabled the development of present civilizations. Climate change is causing unpredictable heat waves, droughts, heavy rains and also cold spells in places they have seldom occurred.

Climate change already affects the lives of three billion people, and one of the most terrible things happening is the increase of sea level, which will affect a couple of billions more. One of the major points made in the IPCC report is that most of the predicted ill effects of climate change can still be avoided, but the actions against climate change need to be speeded up.

How to avoid making friends in British Columbia?

Tiistai 16.11.2021 klo 13.40 - Mikko Nikinmaa

Climate change ain’t real.

Say that to anybody in British Columbia, if you want to be alone and disliked. First they had temperatures above 40^oC in the summer, and now they have rain, which exceeds even their expectations. It has always rained a lot in BC in the autumn, but now the rains enough to cause flooding in an area known for its heavy autumn rains.

So when talking with British Columbians, start your conversation with the sentence above, if you do not want them to be your friends.

Functions Determine Temperature Effects on Animals and Man

Torstai 30.9.2021 klo 19.05 - Mikko Nikinmaa

Climate change is one of the most studied topics of the present time. The web of science contains approximately 350 000 scientific articles studying the topic. Out of these, around 64 000 have studied the biology of climate change. However, only about 1500 of those appear to be concerned with animal or human physiology. This is very concerning, since any effects of temperature changes must be a result of physiological responses to the change. All the other findings on animals and man will be downstream consequences of the physiological adjustments. In view of the above, the recent compilation of reviews in the Journal of Experimental Biology is very welcome. Since it is open access, everyone can read it at https://journals.biologists.com/jeb/issue/224/Suppl_1.

As an example, polar bears have become iconic victims of climate change. There are several documentaries about skinny and diseased creatures about to succumb to increased temperatures as they find less food, when sea ice decreases because of an increase in temperature. However, if that were the only problem they are facing, their plight would probably be tolerable. But since their food availability is decreased, they need to spend an increased amount of energy to catch the prey. Because of the sea ice loss, the energy needed for locomotor activity is 3-4 times higher than expected. Another problem with endotherms is that an increase in temperature is less well tolerated than a decrease. Further, an increase in temperature is a serious problem in dry environments because water loss increases.

For ectothermic animals, temperature increase causes various problems. Dive durations of reptiles, turtles and amphibians decrease by about a third. This translates directly to decreased feeding efficiency. The thermal niches of fish become decoupled from the light-dark rhythms, which function as cues for reproduction etc. When thinking about thermal niches, it appears that both tropical and polar fish tolerate changes in temperature less well than temperate ones. Two overall problems are apparent in translating most temperature studies on fish to climate change scenarios. First, the temperature changes due to climate change are usually much slower than temperature changes imposed on fish in experiments. Second, individual variation as an important component of temperature responses of fish is hardly ever considered. Also, one knows very poorly, what the actual physiological mechanisms behind the measures of thermal tolerance are.

The major reasons why our understanding of physiological mechanisms behind the responses to climate change are poor is due to the fact that functional studies have not been considered important. However, any ecological or genetic response can only occur, if physiological changes take place earlier. Thus, predicting climate change effects on animal populations requires understanding how animals respond physiologically, not by observing changes that have already occurred (either ecologically or genetically).

Climate Change is the Reason for Texan Frost

Tiistai 14.9.2021 klo 16.11 - Mikko Nikinmaa

When it snows in Texas or Spain, the climate denialists rejoice saying that clearly climate change is only scare tactics of the climate believers. Hitherto it has been difficult to give explanations as to why climate change causes the cold spells in the south, heavy rains in Central Europe and extreme heat spells in the Arctic. However, two recent articles clarify the situation significantly, the ones by Osman et al in PNAS (PNAS September 21, 2021 118 (38) e2104105118; https://doi.org/10.1073/pnas.2104105118) and Cohen et al in Science (Science 3 Sep 2021, Vol 373, Issue 6559, pp. 1116-1121; DOI: 10.1126/science.abi9167). Below I try to summarize my understanding of the findings presented.

Much of the weather in North America and Europe is affected by North Atlantic Jetstream. The rains and heat spells depend on its position. With increasing mean temperature of the arctic it appears that North Atlantic Jetstream undulates more and its position shifts northwards as Arctic temperature increases. Southward undulations mean that cold air from the Arctic reaches more southern latitudes than earlier and northward undulations that southern hot air reaches north. Presently, changes in the general position of the North Atlantic Jetstream and its undulations are so variable that consistent weather changes do not occur – cold summer can follow a hot one and dry autumn a wet one. However, it can be predicted that by 2060 the jetstream has moved generally so much north that Southern Europe becomes consistently drier and Central Europe and Scandinavia wetter than currently.

The Arctic temperature increases more rapidly than temperatures elsewhere. This is called Arctic Amplification (AA). As a result of this general AA, it appears that mid-latitudes experience cooling of winters, as the still cold arctic air is able to stream to southern latitudes. This is the result of Stratospheric Polar Vortex stretching southwards, which may, in my opinion, coincide with the southward undulations of the North Atlantic Jetstream (where NAJ occurs). However, these are clearly independent in continental North America and Asia (where there is no NAJ). So, cold weather in southern areas can be a consequence of climate change.

In any case the predictability of weather patterns decreases markedly with climate change. As a consequence, agricultural production all over the world may be reduced, leading to increased problems for the mankind.

IPCC Report - Nothing New But Still Alarming: Immediate Global Climate Actions Are Needed

Tiistai 10.8.2021 klo 12.11 - Mikko Nikinmaa

The IPCC report on the physical science basis of climate change was released yesterday. It is not likely that many people read all its 1300 pages. However, it is enough if the 65-page summary for policymakers is read through. In fact, all of the findings and information are in line with what scientists have been saying for the past 50 years: ever since the book “Limits to Growth” was published in 1972. The scientists’ warning has been repeated twice – or three times, if you take into account the recent addition to the 2019 data. This is now the 6^th IPCC report. The scientists’ voices have come louder and more demanding: actions are needed. What was a worst case possibility in 1970’s has become likelihood with high probability, if drastic actions are not done.

 With the wildfires raging throughout the world, many massive heat waves, heavy rains causing floods and droughts in various parts of the world one would think that people accept that climate change is taking place, and demands global action. Hot temperature extremes and heavy precipitation have increased frequency in most places, and there is not a single area in the world where their frequency would have decreased. Similarly, droughts have increased in many parts of the world, but decreased only in one: Northern Australia. Despite this, a significant proportion of people think that climate change is a hoax, and many politicians are of the opinion that one must not do any environmental actions if they interfere with economic growth and decrease the economic competitiveness.

Quite often those, who deny climate change, say that for example last year it snowed in Spain and Texas, and that very high temperatures have been reported earlier, e.g. in 1998. That one year is climate denials’ favourite, since having that as a basis, there has hardly been any change in average global temperature afterwards. However, it is known and repeatedly pointed out by climate scientists that natural variability dampens or accentuates changes in the short term. In fact, the probability of most types of extreme weather increases with climate change: the likelihood of both droughts and heavy precipitation doubles even if the temperature increase can be kept at 1.5^oC; if drastic climate actions are not done, droughts become 5x more common, and heavy precipitation occurs 3x more frequently than now.

The climate problem is global. Thus, we cannot say that our country is doing its share, now the other nations should do the same. Combatting climate change in developing countries should be a primary focus of the rich countries, and rich individuals: what is the point of spending billions to military or space flights if the world is in peril. Even if the report is gloomy, we have all the technology and other means to still prevent the climate catastrophe. What is required is that we start to think globally instead of nationalistically.