Global warming will continue even after carbon emissions are reduced

Text from Research in Estonia page (link to the original post)

Ülo Mander, a professor of physical geography and landscape ecology at the University of Tartu, says that even though pursuant to the Paris climate agreement less carbon should be released into the atmosphere, global warming will still continue. The continuing of global warming means, for Estonia for example, that by the end of the 21st century, snowy winters will be just a memory.

“Unfortunately, global warming will not stop – that’s the main message,” noted Ülo Mander in a presentation made at the Estonian Ecology Conference. The CO2 content of the atmosphere, air temperatures and the sea levels will continue to rise after the burning of fossil fuels has stopped. In his opinion, focus should rather be on creating policies and technologies for handling the warming.

In 2013, the Intergovernmental Panel on Climate Change (IPCC) issued a report, according to which, to keep the increase in temperature below 2 °C, the population should prevent the relative level of CO2 from rising above 450 ppm.

For the Paris Agreement, 195 countries submitted long-term national climate action plans for reducing the amount of emissions. But the truth is, that even after reducing emissions, the temperature won’t decrease but rather will continue its ascent.

For this claim to make sense, Ülo Mander first explained, in simple terms, what influences global warming.

Carbon dioxide (CO2), methane (CH4) and laughing gas (N2O) are the three gases created by human activity which increase the greenhouse effect the most. These gases prevent thermal radiation from leaving the earth’s atmosphere and thus create global warming. The ozone layer is broken down by laughing gas, which is a so-called legal gas. Most laughing gas is produced as a byproduct of farming, agriculture, and also through the drainage of organic soils.


Pic from here

How is the relative content of carbon dioxide measured?

By analysing ice cores drilled in Antarctica, information is gathered regarding how the content of CO2 in the earth’s atmosphere has changed over the last 400,000 years.

The concentration of carbon dioxide in the air began to be measured in the mid 1950s at the Mauna Loa geophysics observatory on the island of Hawaii and in April 2013, for the first time in the last million years, the CO2 content exceeded 400 ppm or 0.04 per cent of the total composition of the earth’s troposphere.

Climate change has ten features, seven of which will continue increasing as global warming continues. The other three (glaciers, sea ice and snow cover) are related to melting.

A rise in temperature has been noted in both continental and marine conditions. Global warming manifestations and forecasts according to IPCC are as such:


  • In the last 30 years, every decade has been considerably warmer than the last. Warming has been increasing since 1850.
  • 1983–2012 was the warmest 30-year period of the Northern Hemisphere in the last 1400 years.
  • Global precipitation variability is smaller compared to changes in temperature.
    It is highly likely that the number of cold days and nights has globally decreased and the number of warm days/nights has increased.


  • The extra heat accumulated in the oceans plays the biggest role in the warming of the global climate system.
  • The 75-metre upper layer of the ocean has warmed the most, increasing 0.11 degrees over ten years. The heat of the ocean’s surface layers also reaches the deeper layers and can influence global water circulation, i.e. the system of currents. This last change will, however, happen with a probability of 11–36 per cent and will take a considerable amount of time. The ocean will continue to warm in the 21st century.
  • About 70 per cent of shores will see a 20 per cent rise in the sea level.


  • The ice cover of the Arctic Ocean is melting at an accelerated pace and will, in the near future, disappear during summer months.
  • The snow cover of the Northern Hemisphere decreases significantly during spring.
  • Glaciers are melting at an accelerated pace.
  • Permafrost continues to melt, which might cause an increase in the release of CO2 and methane into the atmosphere.

Thus, global warming is a fact corroborated by data. How the Paris Agreement’s objective to reduce CO2 emissions will influence global warming is a separate question.

Here, the most important factor is perhaps the fact that the ocean has a considerable capacity for storing additional heat and will release heat long after we have limited fossil fuel emissions – a goal of the Paris Agreement.

Greenhouse gas emissions undoubtedly decrease faster than the air temperature and sea level increase.

Mander points out that geographical zones which experience high amounts of precipitation will have even more. And places, which are prone to droughts will see a drop in precipitation. There is already a lack of rain in the Mediterranean region and this will only intensify.

In Estonia, the amount of precipitation is expected to rise, but it varies by region. “One thing is certain: winter and spring will get warmer faster. This is already the current trend – snow cover has become thinner and lasts for a shorter period of time, and this trend will continue. Based on these harsh scenarios, Estonia will probably have no sustained snow cover by the end of the 21st century,” explained Mander.

But why would global warming continue after the implementation of limiting measures?

According to a report by IPCC made in 2001, due to melting glaciers, the sea levels will continue to rise for many millennia. Even if we are able to reduce CO2 emissions in less than a hundred years, global warming will continue for many years.

“Only four per cent of the entire CO2 emission is anthropogenic, about 95.8 per cent is from natural sources. Anthropogenic sources include land use, which contains both natural as well as anthropogenic components, but we are currently not able to accurately evaluate these different flows,” explained Mander. In the continental ecosystem there is a lot of uncertainty in terms of CO2 as well as methane.

Even if we reduce the effect of the components of fossil fuel and land use (methane), we are unaware of the size of the balance between CO2, methane and laughing gas. It is, however, not known how much CO2 vegetation binds or how much of it is re-emitted into the atmosphere by plants. The same can be said, for example, of methane and laughing gas: we do not know how much is emitted into the atmosphere naturally. The largest and most dangerous time bomb, however, is the melting of methane ice.

Ülo Mander concluded his presentation with the following: “Adaptation is definitely important. We should be ready, if only technically, for deep droughts and floods. This is all expensive, but survival is expensive. If we do not discuss the use of the world’s resources, then, in my opinion, there is no escape.”

The translation of this article from Estonian Public Broadcasting science news portal Novaator was funded by the European Regional Development Fund through Estonian Research Council.

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New publication – Global database of plants with root‐symbiotic nitrogen fixation: Nod DB

Text by Lauri Laanisto

It´s really a very simple paper! A (relatively little) database containing information about all the plants (on genus level) that fix nitrogen from the soil. Somehow this information has not been available so far in a comparable and trustworthy way. Plus, it´s readily accessible – in a form or Excel table. Together with some additional taxonomic information for both plant and bacterial taxa, estimation of consensus, comparison with other sources that have tackled the same topic. To an ecologist, especially macroecologist, this dataset is a great source for easily getting potentially crucial trait added to your dataset. Because, as you can see from the GBIF-data based analysis (see the graph below), the proportion of N-fixing plants can differ quite a lot on global scale.

Citation: Tedersoo, L., Laanisto, L., Rahimlou, S., Toussaint, A., Hallikma, T., & Pärtel, M. (2018). Global database of plants with root‐symbiotic nitrogen fixation: Nod DB. Journal of Vegetation Science, (link to full text)

nod db

Figure 2 from the paper: Species richness of N-fixing vascular plants relative to total species richness as based on all GBIF vascular plant records with coordinates. Relative richness is calculated per equal area polygons (ISEA3H) with size ca 7,000 km2. Colours show quantiles. Only terrestrial polygons hosting more than 50 records are shown.


Plants associated with symbiotic N‐fixing bacteria play important roles in early successional, riparian and semi‐dry ecosystems. These so‐called N‐fixing plants are widely used for reclamation of disturbed vegetation and improvement of soil fertility in agroforestry. Yet, available information about plants that are capable of establishing nodulation is fragmented and somewhat outdated. This article introduces the NodDB database of N‐fixing plants based on morphological and phylogenetic evidence (available at and discusses plant groups with conflicting reports and interpretation, such as certain legume clades and the Zygophyllaceae family. During angiosperm evolution, N‐fixing plants became common in the fabid rather than in the ‘nitrogen‐fixing’ clade. The global GBIF plant species distribution data indicated that N‐fixing plants tend to be relatively more diverse in savanna and semi‐desert biomes. The compiled and re‐interpreted information about N‐fixing plants enables accurate analyses of biogeography and community ecology of biological N fixation.

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EcolChange seminar – Kitty Gehring about the effects of climate change and invasive species on root-fungi

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Prof. Catherine (Kitty) Gehring is based at the Northern Arizona University, AZ, USA. She is visiting the Department of Botany to act as opponent at the PhD defence of Lena Neuenkamp in June 6th, 10.15 at Lai 40, Vaga auditorium (Lena´s thesis can be found here).

Title of the talk: Root-associated fungi influence host response to climate change and invasive species

Time: Tuesday, 05. June 2018 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)


The current situation of root-fungi in the US is sad (pic from here)!

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EcolChange seminar – Borja Jimenéz-Alfaro about the biogeography of plant communities

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Dr. Jimenéz-Alfaro is senior postdoctoral researcher at University of Oviedo, Spain. He is visiting the Department of Botany, Tartu University to act as opponent at the PhD defence of Kersti Riibak on Monday, May 28th at 10.15 in Vaga auditorium (her thesis is available here).

Title of the talk: The biogeography of plant communities 

Time: Tuesday, 29. May 2018 at 10.15

Place: Tartu, Lai 40-218 (Vaga auditorium)


Biotic interactions supressing dispersal into new habitats (pic from here)


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EcolChange seminar – Leonardo Magalhães about what affects Amazonian biodiversity

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Leonardo Magalhães is a Brazilian doctorate student and is currently visiting the macroecology team of the Department of Botany

Title of the talk: Amazonian biodiversity linked to past and current human influence

Time: Thursday, 24. May 2018 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)


Humans have emerged as a global force that is transforming the ecology of an entire planet. It is no longer possible to understand, predict, or successfully study ecology without understanding human effects over the long term. Amazonian diversity is now in the focus of a hot debate about human influence.

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EcolChange seminar – Robert Szava-Kovats about cognitive bias in conservation

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Robert Szava-Kovats is researcher at the macroecology team of the Department of Botany.

Title of the talk: Conservation biology: a suitable habitat for cognitive bias 

Time: Wednesday, 16. May 2018 at 13.15

Place: Tartu, Lai 40-218 (Vaga auditorium)


Cognitive bias – the act of holding onto one’s worldview, that is one’s preferences, beliefs and values, regardless of contrary information – is to a particular degree a part of everyone’s psyche, scientist or layman. Conservation biology is distinct from many other scientific disciplines because it is value-laden, and therefore reflects the worldview of its practitioners. This distinction adds another dimension to the impact of cognitive bias.  We examine the role of cognitive bias on publication and peer-review in the field of conservation biology and reflect on its implications on conservation biology’s policy-driven objectives.

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New publication – Structural controls on photosynthetic capacity through juvenile‐to‐adult transition and needle aging in Mediterranean pines

Text by Vivian Kuusk

Mediterranean pines are known for stress tolerance as they live in harsh environment where shortage of water is very common. All pines, but especially Mediterranean ones grow and keep different looking needles while they are young or adult. Young needles are quite soft and contain mainly photosynthetic tissue and have much less supportive tissue than adult needles. The study is about finding out the advantage of juvenile needles for the tree.

We concluded that due to different needle structure there are age-dependent differences in needle photosynthetic potentials, nitrogen use efficiency and mesophyll conductance that contribute to juvenile plants early growth and establishment. The experiment clarified more deeply our understanding of structural limitations to photosynthesis. Young seedlings need favorable conditions to survive, but when the chance is present, they grow needles that are as low cost and as efficient in photosynthesis as possible. Only after proper establishment of root system and couple of shoots, more durable needles are grown.

Citation: Kuusk, V., Niinemets, Ü., & Valladares, F. (2018). Structural controls on photosynthetic capacity through juvenile‐to‐adult transition and needle aging in Mediterranean pines. Functional Ecology, DOI: 10.1111/1365-2435.13087 (link to full text)


Old pine-man (pic from here)


  1. Needle photosynthetic potentials strongly vary among primary (juvenile) and secondary (adult) needles (heteroblasty) in Pinus species, but there is limited understanding of the underlying structural, diffusional and chemical controls.
  2. We studied differences in needle photosynthetic characteristics among current‐year juvenile and adult needles and among different‐aged adult needles in Mediterranean pines Pinus halepensis Mill., P. pinea L. and P. nigra J. F. Arnold subsp. salzmannii (Dunal) Franco, hypothesizing that needle anatomical modifications upon juvenile‐to‐adult transition lead to reduced photosynthetic capacity due to greater limitation of photosynthesis by mesophyll conductance and due to an increase in the share of support tissues at the expense of photosynthetic tissues. We also hypothesized that such alterations occur with needle ageing, but to a lower degree.
  3. Photosynthetic capacity per dry mass was 2.4‐ to 2.7‐fold higher in juvenile needles, and this was associated with 3.4‐ to 3.7‐fold greater mesophyll diffusion conductance, 2‐ to 2.5‐fold greater maximum carboxylase activity of Rubisco (Vcmax) and 2.2‐ to 3‐fold greater capacity for photosynthetic electron transport (Jmax). The latter differences were driven by modifications in mesophyll volume fraction and changes in the share of nitrogen between structural and photosynthetic functions. Analogous changes in photosynthetic characteristics occurred with needle ageing, but their extent was less.
  4. These results indicate that conifer foliage photosynthetic machinery undergoes a profound change from a fast return strategy in juveniles to slow return stress‐resistant strategy in adults and that this strategy shift is driven by modifications in foliage biomass investments in support and photosynthetic functions as well as by varying mesophyll diffusional controls on photosynthesis. Changes in needle morphophysiotype during tree and needle ageing need consideration in predicting changes in tree photosynthetic potentials through tree ontogeny and during and among growing seasons.


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EcolChange seminar – Ignacio Agramonte about landscape structure and ecosystem services

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Ignacio M. Hernández Agramonte is senior specialist at the macroecology team of the Department of Botany.

Title of the talk: Importance of historical and present landscape structure on the provision of individual ecosystem services

Time: Thursday, 03. May 2018 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)


The art of landscaping (pic from here)


Changes in landscape structure and habitat spatial configuration have strong effects on biodiversity and ecosystem processes, resulting also in profound impacts on the provision of ecosystem services. However, for a number of ecosystem characteristics and processes, changes in landscape structure do not have immediate effects but are manifested after a considerable time-lag. To evaluate the status and future trends of the provision of vital ecosystem services in changing landscapes, it is crucial to identify and incorporate the possible time-lags effects to the ecosystem services assessment.


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EcolChange seminar – Alar Astover about soil R&D

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Alar Astover is professor of soil science at the Estonian University of Life Sciences.

Title of the talk: R&D activities in Chair of Soil Science at the Estonian University Life Sciences 

Time: Thursday, 26. April 2017 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

The consequences of messing with nature

Our precious (pic from here)


Our focus is to study soil quality and processes in agroecosystems. During the last years interdisciplinary research related to soil organic matter and CNP cycling has increased. We are aiming to combine basic and applied research from micro- to landscape scale in an effective way.

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EcolChange seminar – Riin Tamme about global patterns in plant traits

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Riin Tamme is researcher in the team of macroecology at the Department of Botany.

Title of the talk: Global patterns in plant traits 

Time: Thursday, 19. April 2017 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)



Plant traits vary hugely across the world, but it’s only recently that plant trait research has moved from local and regional scale to global scale. The growing availability of standardised plant trait datasets from different regions has helped us to unravel how plant traits really vary globally and what are the underlying factors behind these patterns. Knowledge of these global patterns in plant form and function can then give further insights into the biogeography of species richness as well.

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