Atmospheric Carbon Dioxide Levels Research Articles

Direct atmospheric cryogenic carbon capture in cold climates

Fossil fuel burning and land clearing have significantly increased atmospheric carbon dioxide (CO2) levels from a preindustrial concentration of about 280 ppm to over 420 ppm, leading to a rise in global temperatures and ocean acidity. Although there exist both natural ways to capture carbon, such as trees, oceans, and wetlands, and engineered approaches, such as capturing CO2 at the source of flue gas, even under extremely optimistic scenarios, additional methods to capture carbon directly from the atmosphere are needed. This account provides a critical examination of the concept, as well as a review of pioneering early-stage research pertaining to cryogenic CO2 capture plants designed for deployment in extremely cold environments, such as northern Canada, Siberia, or Antarctica. Based on theoretical analysis, such a plant could desublimate CO2 at an energy cost of around 30 GJ/tonne CO2, which is about an order of magnitude higher than chemical-based approaches. With further research and technological advancements, the cryogenic direct-air capture (DAC) of CO2 could potentially become economically feasible.

Eruption history of the Columbia River Basalt Group constrained by high-precision U-Pb and 40Ar/39Ar geochronology

Large igneous province volcanism of the Columbia River Basalt Group (CRBG) has been suggested to play a causal role in elevated global temperatures and atmospheric carbon dioxide levels of the Miocene Climate Optimum (MCO). However, assessing the connection between volcanism and warming is dependent upon an accurate and precise chronology for the timing and duration of CRBG emplacement. Building on our previous work (Kasbohm and Schoene, 2018), we present fifteen new high-precision ages, using CA-ID-TIMS U-Pb on zircon and multi-collector 40Ar/39Ar on basaltic groundmass, to provide a detailed dual-chronometer timeline for CRBG eruptions. We use both sets of new ages and precise stratigraphic positions of our samples in an integrated Markov Chain Monte Carlo model to calculate average long-term emplacement rates for main-phase CRBG volcanism of 0.2-0.9 km3/a, with a high likelihood of one prominent hiatus of 60-120 kyr duration occurring after main-phase emplacement. We analyzed trace elements and hafnium isotopes of each dated zircon from CRBG interbeds. The compositions are consistent with both Cascades subduction volcanism and evolved syn-CRBG volcanism proximal to the depositional area. Our age model also yields ages for all magnetic field reversals during the main phase of CRBG emplacement, which can be used to improve calibrations of Miocene paleoclimate records. We find that main-phase CRBG emplacement is coincident with the greatest sustained warmth of the MCO in astronomically-tuned records. Our work shows the power of using both U-Pb and 40Ar/39Ar geochronology in an integrated stratigraphic context to assess data reliability and develop the most robust age model possible for large igneous province emplacement.

Control of atmospheric carbon dioxide level through integrated carbon taxation-reforestation policy: a modeling study

Control of atmospheric carbon dioxide level through integrated carbon taxation-reforestation policy: a modeling study

Role of microbial carbon capture cells in carbon sequestration and energy generation during wastewater treatment: A sustainable solution for cleaner environment

Unusual increases in population around the world have prompted issues with energy supply, environmental changes, and waste management, all of which demand for advancements in waste-to-energy systems. With the increasing anxiety for worldwide environmental change, a renewable, effective and sustainable power generation from wastewater is imperious. Although plants and human life can benefit from exposure to CO2, excessive CO2 can have a negative impact on your health. More harmful consequences on the ecosystem may potentially emerge from an increase in atmospheric carbon dioxide levels. The current review is coordinated towards assessing the ability of microbial carbon capture cells (MCC) for concurrent carbon sequestration and energy generation during wastewater treatment. This review article presents a technique of microbial CO2 fixation, metabolic pathways and role of genetically modified micro-organisms for CO2 capture and sequestration. The function of MCC including its possible applications is affected by various factors, which are outlined. The potential utilization of micro-organisms in energy generation and wastewater treatment when consolidated in a MCC has been discussed. This review summarizes the approaches including recent advances, challenges and perspectives that employ microbes to capture and sequester CO2, bioconversion of CO2 to energy generation.

Carbon emissions from emerging glacier-fed Himalayan lakes

Glacial lakes are rapidly emerging in the Himalayas as glacier mass wastage rates in the region nearly doubled in recent times. Yet, the weathering‑carbon feedbacks in the glacial lakes are poorly constrained limiting our ability to predict how these newly forming and expanding lakes will modulate atmospheric carbon dioxide levels. In this study, we quantify the sources and process of carbon cycling in small-sized (≤0.4 km2) glacier-fed Himalayan lakes during summer time and evaluated the role of glacial lakes and streams in the atmospheric carbon budget. We find that glacier-fed Himalayan lakes and streams are expected to emit CO2 up to 1746 ± 139 mg C m−2 d−1 and 1960 ± 176 mg C m−2 d−1, respectively, which is mostly controlled by dissolved inorganic carbon (DIC) fluxes. Using the glacial-lake inventory database, we estimate that the smaller glacial lakes in the Himalayas have the potential to emit ∼0.1 Tg C yr−1 to the atmosphere. As recent findings suggest that the existing lakes in the “Third Pole” have undergone >45% expansion in an area with a rapid expansion rate of +14.44 km2 yr−1 between 1976 and 2018, we conclude that CO2 emission from these smaller and newly developed Himalayan glacier-fed lakes and streams would be an important emerging component of carbon budgets in the glacierized Himalayan catchments, and its contribution will increase in future. Glacial lakes are emerging worldwide in response to melting glaciers. However, their role in carbon cycling is still underexplored. The lack of direct observational datasets on carbon fluxes, as well as their CO2 feedback mechanisms in glacial catchments has made it challenging to determine the impact of glacier-weathering‑carbon feedbacks on the concentration of atmospheric CO2. Here, we quantify the CO2 emitting potential of glacier-fed lakes and streams. By studying the carbon biogeochemistry of small (≤0.4 km2) glacier-fed Himalayan lakes and streams, we show that small lakes are a significant emitter of atmospheric CO2 controlled by dissolved inorganic carbon. We suggest that CO2 emission from small glacial lakes is an emerging—and not an inert—component of the regional carbon budget. Small glacial-fed Himalayan lakes emit ∼ 0.1 Tg C yr−1 to the atmosphere contributing to the annual carbon budget estimates of glacierized Himalayan catchments.

Deep eutectic solvent-modified mesoporous silica for CO2 capture: A new generation of hybrid sorbents

The escalating level of atmospheric carbon dioxide (CO2) is currently one of the most pressing environmental concerns for scientists. Consequently, a wide range of sorbents are investigating for their CO2 uptake ability. Studies showed that morphology-controlled mesoporous silica (MPS) and deep eutectic solvents (DESs) perform exceptionally well towards CO2 capture. However, based on their respective physicochemical properties, both MPS and DES systems have their own drawbacks when used separately. A novel strategy is adopted here by combining MPS and DES [choline chloride: ethylene glycol (ChCl: EG):: 1: 2 mol ratio] to prepare a hybrid high-performing porous sorbent - porous DES (PDES) for CO2 capture. PDES has shown superior CO2 capture capacity relative to the DES (ChCl: EG) alone. CO2 capture efficiency of PDES system was further improved by adding superbases 1,5-diazabicyclo[4.3.0]–non-5-ene (DBN). DBN-added PDES system exhibited remarkable CO2 uptake efficiency of 72.4 mg/g (mg of CO2 captured/g of liquid media) and excellent CO2 absorption-expulsion reversibility. The work establishes that a functional MPS-DES combination can enhance CO2 absorption dramatically creating a new generation of high-performing, inexpensive, environmentally-friendly, and widely accessible porous liquid material as effective CO2 sorbent.

Effects of Climate Change and Air Pollution on Perinatal Health.

Climate change is often framed as an environmental concern; however, the burning of fossil fuels both directly and indirectly impacts air quality and, thus, human health. Gas byproducts of combustion lead to increased levels of atmospheric ozone and carbon dioxide, which in turn elevate surface temperatures of the earth. This process exposes individuals to respiratory irritants and contributes to increased frequency of natural disasters such as wildfires, negatively impacting respiratory health. Normal physiologic changes in the respiratory system make pregnant people particularly vulnerable to the effects of air pollution. Asthma and allergic rhinitis are 2 common respiratory diseases that can be triggered by poor air quality. Solutions to limit the impact of climate change on respiratory disease include risk mitigation and reduction of fossil fuel consumption on individual, organization, and community levels. Midwives are well positioned as clinicians to educate people about individual strategies to reduce environmental exposure to respiratory irritants and advocate for policy changes to limit future health effects of climate change.

Carbonate diagenesis: A celebration of the work of John Anthony Dawson (Tony) Dickson

Carbonate diagenesis: A celebration of the work of John Anthony Dawson (Tony) Dickson

What is the long-term demand for liquid hydrocarbon fuels and feedstocks?

Liquid hydrocarbons made from crude oil serve many functions: (1) a dense, easy-to-store, easy-to-transport energy source, (2) a method for daily-to-seasonal energy storage, (3) a chemical feedstock, (4) a chemical reducing agent and (5) a method to enhance high-temperature heat transfer in many furnaces and industrial processes. Liquid hydrocarbons can be produced and used without increasing atmospheric carbon dioxide levels if made from non-fossil feedstocks such as carbon dioxide or biomass. Understanding future liquid hydrocarbon demand is the starting point in assessing the viability of such options. Our assessment is that U.S. demand for liquid hydrocarbons is unlikely to go below the equivalent of 10 million barrels per day of crude oil but could be as high as 20 million barrels per day. The costs to replace liquid hydrocarbons increases rapidly at lower liquid hydrocarbon consumption rates. Hydrocarbon biofuels from cellulosic feedstocks can meet such demands if produced with large external inputs of heat and hydrogen. Options based on more limited feedstocks (starches, plant oils, sugars, etc.) can’t meet such demands.

The pervasive impact of global climate change on plant-nematode interaction continuum.

Pest profiles in today's global food production system are continually affected by climate change and extreme weather. Under varying climatic conditions, plant-parasitic nematodes (PPNs) cause substantial economic damage to a wide variety of agricultural and horticultural commodities. In parallel, their herbivory also accredit to diverse ecosystem services such as nutrient cycling, allocation and turnover of plant biomass, shaping of vegetation community, and alteration of rhizospheric microorganism consortium by modifying the root exudation pattern. Thus PPNs, together with the vast majority of free-living nematodes, act as ecological drivers. Because of direct exposure to the open environment, PPN biology and physiology are largely governed by environmental factors including temperature, precipitation, humidity, atmospheric and soil carbon dioxide level, and weather extremes. The negative effects of climate change such as global warming, elevated CO2, altered precipitation and the weather extremes including heat waves, droughts, floods, wildfires and storms greatly influence the biogeographic range, distribution, abundance, survival, fitness, reproduction, and parasitic potential of the PPNs. Changes in these biological and ecological parameters associated to the PPNs exert huge impact on agriculture. Yet, depending on how adaptable the species are according to their geo-spatial distribution, the consequences of climate change include both positive and negative effects on the PPN communities. While assorting the effects of climate change as a whole, it can be estimated that the changing environmental factors, on one hand, will aggravate the PPN damage by aiding to abundance, distribution, reproduction, generation, plant growth and reduced plant defense, but the phenomena like sex reversal, entering cryptobiosis, and reduced survival should act in counter direction. This seemingly creates a contraposition effect, where assessing any confluent trend is difficult. However, as the climate change effects will differ according to space and time it is apprehensible that the PPNs will react and adapt according to their location and species specificity. Nevertheless, the bio-ecological shifts in the PPNs will necessitate tweaking their management practices from the agri-horticultural perspective. In this regard, we must aim for a 'climate-smart' package that will take care of the food production, pest prevention and environment protection. Integrated nematode management involving precise monitoring and modeling-based studies of population dynamics in relation to climatic fluctuations with escalated reliance on biocontrol, host resistance, and other safer approaches like crop rotation, crop scheduling, cover cropping, biofumigation, use of farmyard manure (FYM) would surely prove to be viable options. Although the novel nematicidal molecules are target-specific and relatively less harmful to the environment, their application should not be promoted following the global aim to reduce pesticide usage in future agriculture. Thus, having a reliable risk assessment with scenario planning, the adaptive management strategies must be designed to cope with the impending situation and satisfy the farmers' need.

Effects of acidification on nitrification and associated nitrous oxide emission in estuarine and coastal waters

In the context of an increasing atmospheric carbon dioxide (CO2) level, acidification of estuarine and coastal waters is greatly exacerbated by land-derived nutrient inputs, coastal upwelling, and complex biogeochemical processes. A deeper understanding of how nitrifiers respond to intensifying acidification is thus crucial to predict the response of estuarine and coastal ecosystems and their contribution to global climate change. Here, we show that acidification can significantly decrease nitrification rate but stimulate generation of byproduct nitrous oxide (N2O) in estuarine and coastal waters. By varying CO2 concentration and pH independently, an expected beneficial effect of elevated CO2 on activity of nitrifiers (“CO2-fertilization” effect) is excluded under acidification. Metatranscriptome data further demonstrate that nitrifiers could significantly up-regulate gene expressions associated with intracellular pH homeostasis to cope with acidification stress. This study highlights the molecular underpinnings of acidification effects on nitrification and associated greenhouse gas N2O emission, and helps predict the response and evolution of estuarine and coastal ecosystems under climate change and human activities.

Modeling carbon export mediated by biofouled microplastics in the Mediterranean Sea

AbstractMarine microplastics can be colonized by biofouling microbial organisms, leading to a decrease in microplastics' buoyancy. The sinking of biofouled microplastics could therefore represent a novel carbon export pathway within the ocean carbon cycle. Here, we model how microplastics are biofouled by diatoms, their consequent vertical motion due to buoyancy changes, and the interactions between particle‐attached diatoms and carbon pools within the water column. We initialize our Lagrangian framework with biogeochemical data from NEMO‐MEDUSA‐2.0 and estimate the amount of organic carbon exported below 100 m depth starting from different surface concentrations of 1‐mm microplastics. We focus on the Mediterranean Sea that is characterized by some of the world's highest microplastics concentrations and is a hotspot for biogeochemical changes induced by rising atmospheric carbon dioxide levels. Our results show that the carbon export caused by sinking biofouled microplastics is proportional to the concentration of microplastics in the sea surface layer, at least at modeled concentrations. We estimate that, while current concentrations of microplastics can modify the natural biological carbon export by < 1%, future concentrations projected under business‐as‐usual pollution scenarios may lead to carbon exports up to 5% larger than the baseline (1998–2012) by 2050. Areas characterized by high primary productivity, that is, the Western and Central Mediterranean, are those where microplastics‐mediated carbon export results to be the highest. While highlighting the potential and quantitatively limited occurrence of this phenomenon in the Mediterranean Sea, our results call for further investigation of a microplastics‐related carbon export pathway in the global ocean.

Aboveground carbon storage in Adansonia digitata L. (Baobab) in Mkanana agroforestry and Mangalisa forest reserve in Mpwapwa District, Tanzania

Woodlands are important sinks for the ever increasing levels of atmospheric carbon dioxide, which is directly linked to climate change. Baobab (Adansonia digitata L.) is among the vascular tree species with a long lifespan of 1250 years thus potential for carbon storage though inadequately studied. This study therefore aimed to account for aboveground biomass and carbon in an agroforestry of Mkanana village (with baobabs and sunflower) and Mangalisa forest reserve in Mpwawa District. The allometric model developed for baobabs in dry areas was used for estimation of biomass which was computed as 50% carbon. The mean aboveground biomass of baobabs of 6.952 ± 0.09546 tonnes/tree in Mangalisa forest reserve was higher than 5.538 ± 0.3064 tonnes/tree recorded in Mkanana agroforestry (Mann-Whitney U-Statistic = 94.000, U’ = 531.00, P ˂ 0.0001). On the other hand, the mean aboveground carbon of 3.476 ± 0.09546 tonnes/tree in Mangalisa forest reserve was significantly higher than 2.769 ± 0.1533 tonnes/tree recorded in Mkanana agroforestry (Mann-Whitney U-Statistic = 93.000, U’ = 532.00, P ˂ 0.0001). The results of this study positively contribute to vegetation carbon storage. Sustainable carbon storage in baobabs can be achieved by planting them in reserve areas rather than in agroforestry.

Advances in Designing 3D‐Printed Systems for CO2 Reduction

AbstractThe increasing level of atmospheric carbon dioxide (CO2), and the resultant global warming is a matter of growing concern among scientists, environmentalists, and climate experts across the globe over the past several decades. Numerous attempts are being undertaken today that seek solutions to mitigate this global crisis. This includes designing functional catalysts, devices and reactors to convert greenhouse gasses such as CO2 into useful products like low‐carbon fuels and chemicals, thereby reducing the amount of CO2 considerably in the atmosphere. Advancements in emerging technologies like 3D‐printing can effectively aid in the fabrication of electrodes and devices to tackle the rising CO2 concerns. Low cost, rapid prototyping ability, and printing simple and complex structure are few of the significant merits of this technology. Thus, in this perspective article, discussions on fabricating 3D‐printed (electro)catalysts, customized devices, reactors, etc., via multiple strategies are put forward with emphasis on the electrochemical reduction of CO2. Also, a detailed discussion on the post‐printing treatments, catalyst modifications, and other CO2 mitigation strategies is provided as well. Although studies in this direction are scarcely reported, observations made hitherto show promising possibilities of broadening this field for large scale CO2 reduction reaction applications, and similar catalytic applications in the near future.

Quantitative reconstruction of Early Cretaceous dune morphology in the Ordos paleo-desert and its paleoclimatic implications

Deserts are among the most important terrestrial sedimentary environments and have existed in all periods throughout Earth’s history. In contrast to modern deserts, the ability to quantitatively evaluate the area and desertification degrees of ancient deserts is limited due to the lack of unambiguous proxies. Dune morphology and their spatial arrangements directly reflect the degree of desertification of deserts. Recently, a methodology for obtaining the morphological parameters of dunes was established, although it has not been applied to ancient dunes and deserts in deep time. In the Ordos Basin, both the Early Cretaceous desert and modern deserts (Hobq Desert and Mu Us Desert) were well developed and exposed, which makes the Ordos Basin an ideal place to quantitatively evaluate the paleo-desert based on the proposed methodology. In this study, a total of 698 and 1,490 morphological parameters reflecting the Early Cretaceous desert and modern deserts in the Ordos Basin were obtained, respectively. For the Ordos paleo-desert, our results show that its area was larger and its degree of desertification was more severe than those of modern mid-latitude deserts, including the modern desert in the Ordos Basin, but were similar to those of the modern low-latitude deserts. Our results, therefore, suggest that the Ordos paleo-desert was a non-negligible and large desert during an interval of Earth’s history. Since the other controlling factors, such as regional geography and sources of both the ancient and modern deserts in the Ordos Basin, have remained nearly unchanged, we speculate that it may have been the relatively high temperature, high levels of atmospheric carbon dioxide and relatively low precipitation during the greenhouse period (i.e., Early Cretaceous) that led to the large area and severe degree of desertification of the Ordos paleo-desert.

High Carbonate Alkalinity Lakes on Mars and their Potential Role in an Origin of Life Beyond Earth

The exploration of Mars has revealed that its ancient surface hosted lakes with a dazzling array of chemical and physical conditions and processes. The potential habitability of surface waters has driven studies aimed at understanding whether or not Mars once hosted life. High levels of atmospheric carbon dioxide are probable on early Mars, which means that lakes derived from weathering fluids could have contained substantial carbonate alkalinity. Recent studies show that lakes with high carbonate alkalinity are able to concentrate the phosphate and cyanide that are critical for molecular synthesis in the origin of life. While evidence for carbonate-rich Martian lakes remains limited, NASA’s Perseverance rover may reveal clues about the past existence of such waters in Jezero Crater.

Paleoclimate evolution of the North Pacific Ocean during the late Quaternary: Progress and challenges

• Climate systems force the evolution of orbital-scale NPIW formation. • Deciphering the forcing mechanism on dust fluxes to the North Pacific Ocean. • Model-data comparison expected to play an important role in understanding climate changes. High- and low-latitude climatic processes in the North Pacific Ocean are important components of the global climate system. For example, the interplay among North Pacific atmospheric circulation, ocean circulation, and biological productivity affects atmospheric carbon dioxide levels and marine oxygen concentrations. Here we review recent research on the North Pacific paleoclimatic and paleoceanographic evolution during the late Quaternary and its response to external forcings such as orbital insolation, ice-sheet extent, and greenhouse gas concentrations. First, we summarize the principles and application of relative paleointensity as a critical chronological tool in North Pacific paleoclimate research. Second, we illustrate the latest discoveries on the interaction between North Pacific Intermediate Water formation and high-to-low latitude teleconnection processes. Third, recent progress in linking dust fluxes and marine productivity and their global significance for the carbon cycle are presented. Finally, several key scientific problems are highlighted for future research on ocean-atmosphere-climate interactions in the North Pacific, pointing to the importance of combining paleo-records and modeling simulations. Overall, this review also aims to provide a broad insight into possible future changes of ocean-atmosphere circulation in the North Pacific region under a rapidly warming climate.

Score-driven threshold ice-age models: Benchmark models for long-run climate forecasts

Climate variables are known to be subject to abrupt changes when some threshold levels are surpassed. We use data for the last 798,000 years on global ice volume (Ice), atmospheric carbon dioxide level (CO2), and Antarctic land surface temperature (Temp) to model and measure those long-run nonlinear climate effects. The climate variables have very long and asymmetric cycles, created by periods of upward trends, followed by periods of downward trends driven by exogenous orbital variables. The exogenous orbital variables considered by the Milankovitch cycles are eccentricity of Earth’s orbit, obliquity, and precession of the equinox. We show that our new score-driven threshold ice-age models improve the statistical inference and forecasting performance of competing ice-age models from the literature. The drawback of using our 1000-year frequency observations, is that we cannot measure the nonlinear climate effects of humanity created during the last 250 years, which are known to have generated abrupt structural changes in the Earth’s climate, due to unprecedented high levels of CO2 and Temp, and low levels of Ice volume. On the other hand, the advantage of using low-frequency data is that they allow us to obtain long-run forecasts on what would have occurred if humanity had not burned fossil fuels since the start of the Industrial Revolution. These long-run forecasts can serve as benchmarks for the long-run evaluation of the impact of humanity on climate variables. Without the impact of humanity on climate, we predict the existence of turning points in the evolution of the three climate variables for the next 5,000 years: an upward trend in global ice volume, and downward trends in atmospheric CO2 level and Antarctic land surface temperature.

Prediction of Carbon Dioxide Level Using Statistical Learning and Its Potential Correlation With Global Warming

The Industrial Revolution caused a huge change in the climate of our planet. Since the 19th century, a high level of atmospheric carbon dioxide has contributed to global warming and other environmental problems. We first acknowledge the substantial correlations between the CO2 levels or temperatures and the years before creating our models. In this situation, we propose that the ARIMA model, which combines the auto-regression and moving average models, is essential for issue analysis. In order to estimate CO2 concentrations and land-ocean temperatures, we create polynomial models as well as an ARIMA model with seasonality. Following these hypotheses, we discover that the CO2 concentrations and temperatures have a significant direct link. In order to forecast the future relationships between CO2 concentrations and temperatures, we also attempt to employ polynomial function. We constantly reflect on and reexamine the issues as we construct these models in order to have a greater grasp of the circumstances. Each of our models is also evaluated, and the most precise one is used to make forecasts. Based on Matlab, we can quickly calculate the data, utilize iterations to determine the ideal model parameters, and then display our findings in diagrams.

Analysis of development in solar greenhouses

The move towards a de-carbonised world, driven partly by climate science and partly by the business opportunities it offers, will need the promotion of environmentally friendly alternatives, if an acceptable stabilisation level of atmospheric carbon dioxide is to be achieved. This requires the harnessing and use of natural resources that produce no air pollution or greenhouse gases and provides comfortable coexistence of human, livestock, and plants. This study reviews the energy-using technologies based on natural resources, which are available to and applicable in the farming industry. Among these are greenhouses, which are necessary for the growth of some plants (i.e., vegetables, flowers, etc.) in severe climates. However, greenhouses require some air conditioning process to control their temperature and relative humidity to suit specific plants. To achieve this, a novel air humidifier and/or dehumidifier systems using mop fans had been designed and employed in an experimental greenhouse to evaluate its performance under a controlled environment. This device helped to reduce the energy consumption of the greenhouse whilst providing a pleasant environment for the plants inside the greenhouse. The system was designed taking into account the meteorological conditions, which affect the environment inside the greenhouse. The performance of the system was monitored over a period of time by measuring the temperature and relative humidity of the greenhouse. Results of the monitoring have shown that the system was able to provide comfortable conditions (temperatures of 16-26 oC and relative humidity of 65%) suitable for the plants grown in the experimental greenhouse. It also enabled the minimisation of temperature variation and, hence, avoided the hazard of any sudden climatic change inside the greenhouse.