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• Assisted migration (AM) is being considered to adapt forests to climate change. • We review 104 North American common-garden studies and experiments focused on AM. • Forty-seven species were investigated, but studies focused on commercial conifers. • Recent studies include local environmental variables and effects of extreme weather. • Strengths and weaknesses of studies and pathways for future research are summarized. As greenhouse gas emissions rise unabated and temperatures continue to rise, forest managers have begun to consider assisted migration (AM) of trees as a strategy to adapt forests to climate change. To investigate the risks and benefits of AM, old provenance trials have been repurposed and new common-garden experiments initiated. In this paper, we review three decades of common-garden based research into the adaptation of species and provenances (geographically specific varieties) to current and future climates in North America. Using a filtered data base of 106 papers and reports, we investigate multiple aspects of this work, including subject species, tree response variables and their climatic predictors, statistical techniques, and the patterns of adaptation revealed in results. Although the reviewed work contained valuable insights into provenance-climate relationships, much of this work focused on growth in commercial conifer species and the correlation of that growth with annual or monthly climatic averages. A minority of studies investigated the effects of climate variables with direct mechanistic effects on growth or phenology, including temperature extremes, frost and drought indices, or growing-season duration. Furthermore, recent research has opened new avenues of investigation into the influence of local soil and topographic variables, and even ectomycorrhizal communities over provenance performance. We make the case that future common-garden research into provenance-climate relationships should focus on climatic variables with demonstrated mechanistic connections to growth, survival, and phenology. The effects of extreme weather merit particular attention because extreme weather is likely to be a key determinant of long-term tree health and persistence. [ABSTRACT FROM AUTHOR]

Pastureland maintenance is seen as a land-based measure to reduce dependency on feed concentrates and mitigate greenhouse gas (GHG) emissions from livestock production in the EU, while providing other ecosystems services. This paper assesses potential market-mediated impacts, including global Land Use Change (LUC) and GHG emissions, from increased subsidies to pasture-based livestock production in the EU. A tax recycling strategy (TRS) is simulated against a baseline up to 2030 under the shared socioeconomic pathway 2 (SSP2). This implies a budget-neutral increase in the level of pasture subsidies in individual Member States, as land subsidies for other cropping activities decrease. We employ the computable general equilibrium (CGE) model GTAP in its recursive-dynamic version, GTAP-RDEM, extended with the Multi-Regional Input-Output (MRIO) database FABIO to disaggregate agri-food sectors from 21 to 31. This approach allows considering price- and income-dependent feedbacks when assessing long-run changes in the global economy, improving the sectoral resolution relative to GTAP v10. The policy increases pastureland areas and cattle production in almost all EU Member States, whereas cropland and crop production decrease, causing significant changes across EU agri-food markets. Crop prices increase, leading to the reduced output of intensive animal production sectors, mainly pig and poultry. Cropland areas decrease and most EU countries increase imports of grain, oilseeds, and cakes, essentially soybean cake from Brazil and North America. While GHG emissions decrease in those EU countries where pasturelands expand mainly at the cost of croplands, GHG emissions increase in those countries where pastureland expansion comes with forest loss. As a result, net GHG emissions increase in the EU-27 in 2030 (+2.49 Mt CO 2 -eq). Emissions from LUC in major non-EU grain- and oilseed-exporting countries increase, e.g., by 102.52 Mt CO 2 -eq in Brazil and by 129.17 Mt CO 2 -eq in North America. The simulated policy shows that promoting extensive livestock per se does not meet the objectives of the Common Agricultural Policy and the EU Green Deal. The TRS should be complemented with policies to foster crop diversification and promote the use of domestic feed sources (e.g., legumes) to effectively ensure feed self-sufficiency and that extensive cattle production in the EU does not lead to deforestation in carbon-rich countries. [ABSTRACT FROM AUTHOR]

This paper details a method for residential water consumption modeling within the Integrated Urban Metabolism Analysis Tool (IUMAT), a computational modeling platform for evaluating environmental performance of urban communities under alternative growth scenarios. A bottom-up approach is introduced to generate end-use indoor and outdoor water profiles by applying GLM and Ridge regression methods to Residential End Uses of Water, Version 2 (REU II-2016) dataset and investigating the influence of demographic and climate factors, as well as utility rate structures on patterns of consumption. The data is collected from 2010 through 2013 by nine utilities that operate in North America on 771 and 838 single family units for indoor and outdoor water use respectively. Potential advances to surveying methods as well as the need for tools that allow simultaneous, isolated assessment of educational and technological conservation measures are explained. [ABSTRACT FROM AUTHOR]

Megaherbivores are keystone species whose removal from landscapes can cause cascading ecosystem changes, yet the consequences of Late Quaternary megaherbivore extinctions remain uncertain. This paper tests the Megaherbivory Release Hypothesis (MRH), which posits that the decline and extinction of megaherbivores (body size >1000 kg) during the last deglaciation in eastern North America contributed to the expansion of more palatable hardwood tree taxa, the development of vegetation assemblages with no modern analogue, and increased fuel load and fire activity. Coprophilous fungal spores in lake sediment records are used as proxies for megaherbivore abundance and are essential to testing the MRH through analyses of lead/lag relationships among vegetation composition, megaherbivore abundance, fire, and climate. Although some prior analyses of coprophilous fungal spores from individual sites have supported the MRH, these interpretations have been complicated by 1) discrepancies in the timing of coprophilous spore declines versus megaherbivore extinction timing based on dated vertebrate remains, 2) reliance on a single fungal taxon (Sporormiella) rather than a full suite of coprophilous fungi taxa, and 3) uncertainties in the taphonomic processes that influence fungal spore abundances. To examine the spatiotemporal relationships among megaherbivory, vegetation, and fire, we developed five new multi-taxon coprophilous fungal spore records for comparison with existing pollen, spore, and charcoal records from 14 sites across eastern North America. The MRH was well supported in the northeast and central US, with most sites showing a coprophilous spore decline by ∼14.6 ka followed by a rise of hardwood taxa (∼14.4 ka). However, changes in fire regime varied widely among northeast and central US sites and may have preceded spore declines. The MRH was not well supported in the southeastern US, where a smaller rise in hardwood taxa (∼16.1–13.1 ka) generally preceded the decline in coprophilous spores at individual sites (∼15.8–12.7 ka). These site-level and regional differences suggest spatial variations in the strength of couplings among late-Quaternary megaherbivore extinctions, vegetation composition and structure, and fire regime. Possible explanations for the differences between the northern and southeastern US include (1) differences in landscape heterogeneity of canopy openness and palatability, (2) net primary productivity and sensitivity to top-down trophic effects, (3) megaherbivore density, and (4) climate trends and seasonality at orbital to millennial timescales. [ABSTRACT FROM AUTHOR]

The portrayal of climate change in the news has been a major focus of research over the last decade, reflecting the importance of the media in affecting public opinion and policy. This work has primarily focused on the science of climate change, impacts, and mitigation, yet our understanding on how adaptation is being profiled in the media is limited. In response to this gap, this paper quantitatively examines the coverage and framing of climate change adaptation in four influential North American newspapers between 1993 and 2013. Over the observation period, the total number of articles focusing on adaptation published each year increases, with peaks in reporting in 2007, 2012, and 2013. While adaptation has permeated news coverage, it still remains overshadowed by stories on impacts and mitigation, with increased reporting consistent with increased media attention to climate change over the last two decades. Of the newspaper articles with adaptation content ( n = 271), the majority (53%) focus primarily on stating the need to adapt, as opposed to documenting actual preparations being undertaken for adaptation or profiling actual adaptations that have taken place. The types of adaptation being reported on are predominantly ‘hard’ in nature, profiling techno-engineering based responses to reduce potential climate change impacts, in contrast to ‘soft’ responses that seek to enhance resilience. This representation is particularly evident in reporting in 2012 and 2013. Adaptations being described in the selected newspaper articles are primarily anticipatory in nature up until 2011, after which adaptations are primarily discussed in terms of responding to extreme weather events, specifically in the context of a surge in reporting documented in response to Hurricane Sandy (2012) and flooding in Canada in 2013. [ABSTRACT FROM AUTHOR]

• A template for restoring high elevation five needle pines is presented. • The template includes long term programs that assist in restoration activities done at four spatial scales. • Climate change considerations are integrated into this template at each scale. Many ecologically important high elevation five-needle white pine (HEFNP) forests that historically dominated upper subalpine landscapes of western North America are now being impacted by mountain pine beetle (Dendroctonus spp.) outbreaks, the exotic disease white pine blister rust (Cronartium ribicola), and altered fire regimes. And more recently, predicted changes in climate may reduce HEFNP habitat and exacerbate adverse impacts of fire, beetles and rust. Management intervention using specially designed tactics implemented at multiple scales (range-wide, landscape, stand, and tree levels) are needed to conserve these keystone tree species. A goal of this intervention is to promote self-sustaining HEFNP ecosystems that have both resilience to disturbances and genetic resistance to white pine blister rust in the face of climate change. Many tools and methods are available for land managers, and in this paper, we summarize possible multi-scaled actions that might be taken as steps toward restoration of these valuable HEFNP forests. Long-term programs, such as inventory, mapping, planning, seed collection, seedling production, education, and research provide the materials for effective restoration at finer scales. Stand- and landscape-level passive and active treatments, such as silvicultural cuttings and prescribed fires in both healthy and declining forests, are described in detail and grouped by objectives, methods, and tactics. And last, there are critical pro-active tree-level actions of planting and protection that may be used alone or together to enhance success of other restoration actions. Administrative, policy, legislative, and societal barriers to implementation of an effective restoration effort are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: In the wake of the failures to date of well-publicized multilateral and multi-sectoral mitigation efforts to control greenhouse gases, attention is now increasingly focused on the effectiveness and capacity of national and sub-national level sectoral plans, including forestry, to usher in a new era of adaptation efforts. In Canada, the government of British Columbia spent several years developing its Future Forest Ecosystems Initiative as part of a larger climate change response strategy in the forest sector. Similarly, in the United States, wildfire related events have led to climate change inspired efforts by individual states (e.g., Alaska, California) and the US Forest Service has recently undertaken plans to incorporate climate change considerations in national forest planning beginning with the National Road Map for Responding to Climate Change. This paper highlights a number of shortcomings with both these national and sub-national strategies with respect to the relationships existing between governance, forestry and climate change. It proposes incorporating considerations of governance mechanisms directly into forest sector planning and the need to assess not only natural system level changes but also the extent to which new problems can be dealt with by ‘old’ or ‘new’ governance arrangements. [Copyright &y& Elsevier]

Abstract: Surface water chemistry has changed in response to reduced atmospheric deposition of sulphur and acidity in many regions of Europe and North America. Most of these studies come from acidic or low-alkalinity surface waters under high acidic deposition. Mediterranean climates offer a different biogeochemical context, characterised by streamwaters of higher alkalinity and low acid inputs. In this paper, we use surveys of streamwater chemistry conducted in 1981–1984 and again in 2007 in the Montseny natural park (NE Spain) to test whether streamwaters of these well-buffered catchments respond to changes in atmospheric deposition, which has declined for S during the last decades in NE Spain while remaining about stable for nitrogen. The 23 sampled streams drained heathland, beech forests and evergreen oak forests in relatively undisturbed small catchments underlain by silicate bedrock. Bulk deposition of sulphate at Montseny decreased by 54% while nitrate bulk deposition increased (non-significantly) by 30% in this period. Total N deposition is estimated in the range 15–30kg Nha−1 y−1 for NE Spain. This is well above threshold values (e.g. 10kg Nha−1 y−1) reported as starting nitrogen saturation symptoms in forest ecosystems in Europe. Baseflow sulphate concentrations decreased on average by 47μeqL−1 or 29% of early 1980s concentrations. Baseflow mean nitrate concentrations increased significantly but only from 5.5 to 8.9μeqL−1. Thus, despite decades of high N deposition, these ecosystems appear to be still far from N saturation. Baseflow alkalinity and base cation concentrations increased substantially, probably a combined result of decreased S deposition, enhanced silicate weathering under current higher temperatures, reduced plant cation uptake as vegetation matures, and slightly drier conditions in the survey of 2007. Overall, these well-buffered catchments have shown sizable changes in baseflow chemistry in response to changed atmospheric deposition and other environmental changes. [Copyright &y& Elsevier]

Abstract: Climate change will affect mycotoxins in food. The 2007 Intergovernmental Panel on Climate Change report is reinterpreted herein to account for what may occur with mycotoxins. Warmer weather, heat waves, greater precipitation and drought will have various impacts, depending on which regions of the world and mycotoxin systems are considered. The humidity issues are more complex as some areas will experience drought and others greater precipitation: in vivo data on the effects of moisture on mycotoxins in crops are more ambiguous than those for temperature. In vitro data on fungal growth and mycotoxin production may not relate directly to the situation in the field or post harvest, but are useful for base-line assumptions. The effects of climate in various regions of the world, i.e. Africa, Europe, Asia, Latin America and North America are considered in terms of mycotoxin contamination. Crops introduced to exploit altered climate may be subject to fewer mycotoxin producing fungi (the “Parasites Lost” phenomenon). Increased mycotoxins and UV radiation may cause fungi to mutate on crops and produce different mycotoxins. Whereas there is relevant information on aflatoxins, deoxynivalenol, and ochratoxin A, more mycotoxins require to be considered: Data on patulin are missing. The current paper considers uniquely ergot alkaloids. Amelioration strategies are provided. There is considerable urgency in the need to address these issues. [Copyright &y& Elsevier]

Abstract: Changes in the ocean tide during the 20th century have been reported for several parts of the world by different authors. However, it has not always been clear whether the observed changes have been local or regional in scale. This paper reports on a survey of tidal changes in recent decades using a quasi-global data set of tide gauge information. Little evidence has been found in Europe or the Far East (including Australasia and Asia) for the extensive regional changes to the main tidal constituents reported recently for N America. However, evidence for change in smaller regions can be identified wherever the density of tide gauge information allows. Therefore, it seems that tidal changes may be commonplace around the world, although not necessarily with large spatial scales. All of the reported changes have been difficult to explain. However, it is hoped that quasi-global surveys such as the present one may eventually provide further insights. [ABSTRACT FROM AUTHOR]

Abstract: Climate models provide estimates of climatic change over periods of time in the ancient past. Macrophysical climate models (MCM) differ from the more widely used general circulation models (GCM), in that MCMs provide temporally high-resolution (~100years) and site-specific estimations of monthly values of climate variables such as temperature and precipitation. In this paper, seasonal changes in climate variables are modeled for six 14C-dated fossil localities in North America. Five of these localities represent the time of maximum extent of ice during the most recent glacial episode, the Full Glacial (25+–15ka), including one at the peak of the Last Glacial Maximum (17–15ka). The other locality represents the time as the ice began to recede, the Late Glacial (15–11ka). Seasonal variations in temperature and precipitation modeled by MCM are herein compared with interpretations of seasonal variation based upon oxygen isotopes from serially sampled hypsodont teeth (mostly Equus and Bison) collected from each of these localities. Additionally, the MCM-modeled seasonal variations are used to predict the expected abundances of different plant functional groups (PFG) during those times, especially C3 and C4 functional groups, using modern relationships. These predictions are compared with carbon isotopic values from the same teeth. The importance of atmospheric pCO2 for the relative abundance of plants utilizing the C4 metabolic pathway is discussed, given that glacial episodes are known to have been times of lower atmospheric pCO2. Interpretations of seasonal variability and the relative abundance of C3 versus C4 vegetation based upon isotopes from tooth enamel are in broad agreement with predictions using the MCM and the modern distribution of PFGs with climate variables. The influence of pCO2 on the distribution of C4 vegetation during glacial times appears to be negligible. [Copyright &y& Elsevier]

• Future change in extreme droughts over 5797 North American watersheds was studied. • Two climate model large ensembles were used to assess the change of frequency. • Changes in meteorological droughts are mostly correlated to mean precipitation. • Large increases in the frequency of hydrological droughts are observed over NA. • Projected changes in future extreme droughts get worse for longer return periods. This paper describes projected frequency changes in extreme summer meteorological and hydrological droughts over North American catchments. It uses two large ensemble climate models (50-member CanESM2 and 40-member CESM1) under the RCP 8.5 scenario to robustly assess frequency changes up to the 100-year drought, relative to the 1980–2009 reference period. Meteorological droughts, linked solely to precipitation deficit, are represented by the 1-month Standardized Precipitation Index (SPI), whereas hydrological droughts are characterized by the 1-month Streamflow Drought Index (SDI), based on hydrological simulation using a lumped hydrological model. Results show widely different patterns for future changes in extreme meteorological versus hydrological droughts. Future meteorological droughts show patterns of increasing and decreasing frequency that roughly match future expected changes of mean summer precipitation, although some regions are nonetheless projected to see more frequent extreme meteorological droughts despite increases in mean summer precipitation. The frequency changes for the 100-year meteorological droughts can be quite severe, with up to a 20-fold increase observed over some watersheds. On the other hand, hydrological droughts, which combine the effect of precipitation and temperature changes, show a mostly uniform pattern of large to very large increases in drought frequency. This shows that the projected temperature increase is a main driver of future extreme hydrological droughts, enough to overcome the projected increase in mean summer precipitation for many North American catchments. Projected changes in both meteorological and hydrological droughts get consistently worse for the longer considered return periods. In other words, frequency changes for the 100-year droughts are more significant than those expected for the 2- and 20-year droughts. This gradual worsening toward larger extremes has potentially large societal and economic impacts. The large projected increases in the frequency of extreme hydrological drought frequency (up to 27 times) are likely to severely stress water management systems across North America. [ABSTRACT FROM AUTHOR]

• Climate change may cause reduced forest productivity and higher tree mortality. • We infer white spruce growth limitations from 9795 tree cores from 227 sample sites. • Water deficits make trees vulnerable to climate change in its west-central range. • Future climate projections imply water deficits in the southwest and central boreal. • The north-east may be a climate change refugium due to lack of water deficits. Climate change may cause reduced forest productivity and higher tree mortality due to water deficits that result from increased evapotranspiration. Such limitations may occur in some areas of the North American boreal forest where precipitation is low and warming trends are high. This paper analyzes climatic factors that limit the growth of a commercially important and widespread boreal tree species, white spruce (Picea glauca (Moench) Voss), based on a range-wide dendroclimatological analysis of 9795 trees from 227 sample sites across the North American boreal forest. A bootstrapped response function analysis was conducted for monthly temperature and precipitation variables, and a multivariate regression tree analysis was used to group white spruce populations with similar response coefficients where climatic factors explained 46% of the total variance in response coefficients. The results of this study show that white spruce populations in the west-central boreal forest of North America are the most precipitation-limited group and therefore likely to be most susceptible to climate change. Populations both to the north and south of this group appear less vulnerable, and eastern populations generally do not experience growth-limiting moisture deficits. Regional climate change projections suggest that moisture limitations will become more pronounced in the future, especially for southwest and west-central boreal tree populations. [ABSTRACT FROM AUTHOR]

The Kyoto Protocol introduces the possibility that changes in carbonstock on agricultural and forest land and soils may be counted against countries' commitments to reduce their greenhouse gas emissions. Including activities related to land use change and forestry in the international climate change agreement may stimulate new incentives forsoil-conservation practices domestically. However, a primary criteria for their inclusion relates to the level of accuracy and transparency with which carbon stock changes can be assessed. Parties will alsobe concerned with the wider environmental impact of different sequestration practices, and the impact of offsets on overall emissions targets. This paper examines these issues for agricultural soils, considering recent research in North America. It is argued that incentives for carbon sequestration practices may need to be implemented independently of actual stock changes because farm-level soil monitoring would be very costly. In the USA, priority should be given to establishing incentives for cover crops and to expanding conservation tillage programs. These activities provide a range of ancillary environmental benefits. In contrast, improvements in biomass yield tend to rely on higher fertilizer inputs with their related environmental costs. Carbon accumulated through any of these activities is easily lost if the practices are discontinued, and so assessment procedures are needed that would avoid overestimating sequestration. Annual accumulation in agricultural soils could be equivalent to about 10% of Annex I carbondioxide emissions, and therefore options for limiting sink credits from soils should be considered. [ABSTRACT FROM AUTHOR]