Global change test 3

Institutional Adaptation Options

Adoption of principles for effective policy -Climate change adaptation policy is often impeded by the high level of variance of climate change impacts -It should take into consideration: economic efficiency, flexibility, urgency, low cost, equity, institutional feasibility, unique resources, health and safety, consistency, and private versus public sector. -Effective adaptive policy can be hindered by policymakers' preference to enact short-term planning. Infrastructure planning to withstand future weather extremes Traditional coping strategies -Use of traditional knowledge for water savings techniques International finance -Green Climate Fund - aims to assist developing countries in adaptation and mitigation practices

The Coupled Model Intercomparison Project (CMIP)

An initiative of the World Climate Research Programme (WCRP) The motivation for CMIP: Institutions approached the development of their climate models differently, preventing comparison among them. The goals of CMIP To create a framework for climate model experiments that allowed scientists to analyze, validate and improve GCMs in a systematic way. That allows for a better understanding of the past, present and future climate changes arising from natural, unforced variability or in response to changes in radiative forcing in a multi-model context. Since its inception in 1995, CMIP has been through several generations, and each is more sophisticated In its early years, CMIP experiments modeled the impact of a 1% annual increase in atmospheric CO2 concentrations In later iterations, the experiments incorporated more detailed emissions scenarios, such as the Representative Concentration Pathways ("RCPs"). Setting the GCMs the same way and inputs means that the differences in the climate change projections are due to differences in the models not settings/experiments (like GHG amounts)

Global map of vulnerability

Areas shaded light yellow are on average the least vulnerable and those shaded darker brown are the most vulnerable. The map combines information about the level of vulnerability with the population density to show where both high vulnerability and high population density coincide. There are densely populated areas that are highly vulnerable and highly vulnerable populations in sparsely populated areas. Areas shaded light yellow are on average the least vulnerable and those shaded darker brown are the most vulnerable. The map combines information about the level of vulnerability with the population density to show where both high vulnerability and high population density coincide. There are densely populated areas that are highly vulnerable, but also highly vulnerable populations in sparsely populated areas. There are highly vulnerable populations in countries with overall low vulnerability as shown with sub-national case studies alongside the map. The pie charts show the number of deaths per hazard (storm, flood, drought) event per continental region. This reveals that significantly more fatalities per hazard (droughts, floods, storms) did occur in the past decade in more vulnerable regions. Over 3.3 billion people are living in countries classified as very highly and highly vulnerable, while approximately 2 billion people live in countries with low and very low vulnerability

How Can Attribution Science Be Used?

Attribution science is becoming sufficiently recognized to provide support in legal disputes. The Climate Attribution Database. It facilitates access to the latest research and may support litigation and/or provide policy makers with resources to justify climate policies. Several environmental impacts, such as sea level rise, melting permafrost or snowpack, extreme heat, and ocean acidification can confidently be attributed to climate change. Once an impact has been determined to be influenced by climate change, it's possible to figure out the proportion to attribute to a specific source of emissions. Attribution science can be used to defend climate regulations or to establish standing to sue by showing that certain parties have been harmed by climate change impacts.

The Limitations of Attribution Analyses

Because of natural variability, attribution analyses of extreme precipitation, is more difficult Climate models work with grid boxes that cover large spatial areas; for example, 100 miles by 100 miles. Extreme precipitation, often falls in relatively narrow geographical bands 40 miles wide (for example) and a grid box is bigger than that. For that reason, attribution results are more robust for Heat waves and global average temperature Gradually changing conditions that cover a large area like sea level rise, The extent of Arctic Sea ice. Trying to quantify how much climate change increased extreme precipitation is still challenging and is an area of active research

Where to start with climate change mitigation?

Broadly speaking, there are three strategies: Reduce emissions of greenhouse gases Compensate for them through climate engineering Adapt to climate change Of these three options, mitigation has the most straightforward effect on climate because it attacks the source of the problem. But mitigate what? To be able to address reduction of GHG, it's essential to understand who (countries, industries) emits what and how much.

Melting of the Permafrost

Can accelerate climate change due to release of methane (CH4) locked in frozen soils The carbon locked up as CH4 in permafrost soils is 50 60 times that emitted from fossil fuels in a year The area of permafrost in the Arctic is projected to decline by 20% relative to today's area by 2040 and by 66% by 2080.

General Circulation Models (GCMs)

Climate Models are one of the primary means to understand how the climate has changed in the past and may yet change in the future They simulate the physics, chemistry ad biology of the atmosphere, land and oceans and requires large supercomputers to generate simulations A General Circulation Model (GCM) typically contains enough code to fill 18,000 pages of printed text Many years of work by hundreds of scientists are required to build and improve a GCM It can require a supercomputer the size of a tennis court to run As the science and computational capacity advances, so do models GCMs spatial resolution have increased over the years (more, smaller gridcells) Higher resolution models take longer to run (more calculations). Increasing resolution by a factor of two requires 10 times more computing power Some properties (clouds, evaporation, winds) are not directly coded in a model but are simulated as the result of other individual processes. How models simulate the climate is analog of a soccer team performance. The coach select the players and tactics, but when exactly the team scores and how many times is not determined in the outset of the game

the shareholder rebellions

Climate activists and dissident investors successfully executed a shareholder rebellion within ExxonMobil and Chevron last spring, protesting the companies' continued inaction toward meaningfully curbing carbon emissions. Why it matters: Mark van Baal, who founded Follow This, said the shareholder rebellions mark a "paradigm shift" for investors and a "victory in the fight against climate change".

The Limitations of Attribution Analyses 2

Climate models currently do not have fine enough spatial resolution to deal with the many aspects of extreme precipitation, largely because they lack sufficient computing power. Attribution science will likely become more definitive as more years of data are added to the record and the baseline of risk becomes more robust. As computing power grows, gridcells will become smaller and finer features of the climate will be estimated. While attribution studies are constrained when it comes to determining how much climate change affects specific precipitation events, evidence shows that climate change has made many types of extreme events more common than they were in the past.

Global Climate Models

Computer programs that simulate the Earth's average weather patterns- the climate Designed so that certain known fundamental variables can be changed and then it predicts how the climate adjusts to these new conditions The Earth's climate is intrinsically complex Models are essential to predict how the climate, especially temperature, might change in the future in response to changes in GHG concentrations

Threats to Human Health

Distribution of the mosquito Aedes aegypti - which can spread dengue fever, Zika virus, chikungunya and yellow fever - by duration of time in each region. Increased frequency of heat waves Warmer world favors more toxic molds, fungi, microbes that are harmful to human health Expansion of diseases typical of tropical regions (dengue fever, malaria, yellow fever)

What are the different types of Models?

Early GCMs only simulated one aspect of the Earth system such as in "atmosphere-only" or "ocean-only" models Coupled models have brought these spheres together Can simulate, for example, the exchange of heat and water (through phase changes) between the land and ocean surface and the air above. The most recent subset of GCMs incorporate biogeochemical cycles and are called Earth System Models (ESMs) ESMs can simulate the carbon and nitrogen cycles, atmospheric chemistry, ocean ecology and changes in vegetation and land use, which all affect how the climate responds to human-caused GHG emissions. They have vegetation that responds to temperature and rainfall and, in turn, changes uptake and release of carbon and other GHG to the atmosphere. Regional Climate Models ("RCMs") do a similar job as GCMs, but for a limited area of the Earth. They cover a smaller area and run more quickly and at a higher resolution than GCMs. High resolution mean smaller grid cells -> climate information in greater detail for a specific area. RCMs "downscale" global climate information to a local scale. RCMs still need to be fed in information from GCMs The larger scale model information drives the finer-scale model Caveat: errors or biases in GCMs can be amplified in RCMs

Types of vulnerability

Economic A community that is ill-prepared for the effects of climate change due to lack of financial resources People living at or below the poverty level are the most affected by climate change as they may lack investments in resilient infrastructure and resources to rebuild following a disaster. Geographic Communities that experience the local impacts of climate change, such as rising sea levels or changes in ecosystem services. Island nations and communities that rely on subsistence/rain-fed agriculture are examples of communities that are geographically vulnerable.

Social adaptation options

Enhancing adaptive capacity -Increase the ability to adjust and to moderate potential damage, to take advantage of opportunities or to cope with consequences. Migration -Of humans: It is a form of adaptation as it can lead to diversification of livelihood -Assisted migration of ecosystems: moving plants and animals to a different habitat Insurance -It helps spread the financial cost of extreme events -Climate-risk insurance: often used to improve climate resilience of poor and developing communities by providing post-disaster liquidity for relief and reconstruction

Sea level rise

Flooding is becoming more frequent along the U.S. coastline since the 1950s The rate of increase is accelerating at most locations along the East and Gulf Coasts. The East Coast suffers the most frequent coastal flooding and has experienced the largest increases in the number of flood days. At more than half of the locations shown, floods are now at least five times more common than they were in the 1950s. Flooding has increased less dramatically in places where sea level has not risen as quickly (such as the western US coast)

diversity from fossil fuels

For Boston University, the move was significant. When the student-run group DivestBU first launched eight years ago, university president Robert Brown argued divestment wasn't feasible. But after a "long journey," Brown acknowledged in September that activists successfully swayed the board of trustees to divest and put the university "on the right side of history." Why it matters: "It's a really clear testament to the power of persistence and of young people organizing," says Ilana Cohen, a junior at Harvard and organizer with Fossil Free Divest Harvard. "The way that we won divestment was by making it fundamentally unaffordable for the university to maintain its intransigent and fundamentally unfounded, as well as immoral stance on the issue."

Sixth Assessment Report - 2021/2022

For IPCC AR6, a new set of 5 emissions scenarios are driven by different socioeconomic assumptions These are the "Shared Socioeconomic Pathways" (SSPs). SSP1 and SSP5 envision relatively optimistic trends for human development with investments in education and health, rapid economic growth, and well-functioning institutions SSP5 assumes this will be driven by an energy-intensive, fossil fuel-based economy In SSP1 there is an increasing shift toward sustainable practices. SSP3 and SSP4 are more pessimistic in future economic and social development, with little investment in education or health in poorer countries coupled with a fast-growing population and increasing inequalities. SSP2 represents a "middle of the road" scenario historical patterns of development are continued throughout the 21st century.

Observed Impacts- Heat Waves

Heat waves frequency has increased in the US, from an average of two heat waves per year during the 1960s to six per year during the 2010s. In recent years, the average heat wave in major urban areas has been 4 days long, a day longer than the average in the 1960s. The heat waves in the 1930s remain the most severe in recorded U.S. history. Poor land use practices and many years of intense drought contributed to depleting soil moisture and reducing the moderating effects of evaporation.

How do we know humans are causing climate change?

Hindcasts from model experiments that include increasing GHG are compared with experiments in which pre-industrial levels of GHG and natural forcings (volcanic eruption, variability in solar radiation) are included

Attribution Science at Work 2

Hurricane Harvey in August 2017, was the first major hurricane (Cat-4) to make landfall since 2005 (the year of Wilma and Katrina). It covered a large area with extreme precipitation. It caused floods and over 100 deaths in Texas and Louisiana in 2017 It inflicted $125 billion (2017 USD) in damage. Attribution studies found that climate change made Hurricane Harvey, three times more likely and increased the storm's rainfall by 15 percent.

Agricultural pests

In 2020, East African nations battled with swarms of desert locusts in what was called the worst outbreak the region has seen in decades (Food and Agriculture Organization - FAO) The high numbers of desert locusts presented an alarming threat to food security and livelihoods in the Horn of Africa. One small swarm covering one square km eat the same amount of food per day as 35,000 people Irregular precipitation patterns (excessively rainy wet season followed by droughts) related to climate change can favor locust habitat

Attribution Science at Work

In July 2021, Germany, Belgium, and the Netherlands experienced catastrophic flooding that killed 220 people. There was a 1 in 400 chance of that much rainfall in any given year. An attribution analysis found that climate change made the event 1.2 to 9 times more likely than it would have been 100 years ago. Warming temperatures also increased the rainfall by 3 to 19%. The heat wave that hit the Pacific Northwest in June 2021 caused temperatures higher than ever previously recorded in that region. The heat wave was found to be 2°C hotter than it would have been before the Industrial Revolution. If the world reaches 2°C of global warming (it has currently warmed about 1.1°C), this type of 1 in 1000-year heat wave could occur every 5 to 10 years.

Maladaptation

Is an action taken to reduce vulnerability to climate change that increases the vulnerability of other systems, sectors or social groups Piping water to cities during periodic severe droughts can both lead to a discouragement to preserve water and to reduce water availability for communities from where the water is been taken from Adopting technology (air conditioning) that increases GHG emissions Building levees along rivers to prevent floods may give a false sense of security and attract people to flood prone areas

How Can Attribution Science Be Used? 2

It can help hold emitters liable and sue governments for not sufficiently regulating greenhouse gas emissions. A Dutch court ordered Shell to reduce GHG gas emissions by 45% by 2030 The Philippines' Commission on Human Rights determined that fossil fuel companies have a responsibility to reduce their emissions However, no fossil fuel or power company has been held liable for climate-related damages or a gradual change in environmental conditions. But attribution science is making it possible to quantify increased risks, which will likely result in more lawsuits in the future. Attribution science could also help with climate adaptation. Cities might decide to install more green infrastructure to absorb a projected increase in stormwater. If extreme weather events will likely increase in the future, residents might be persuaded to relocate rather than rebuild. Attribution science is providing new insights to help educate, prepare, and influence global communities as they face the impacts of a warming world.

Adaptation to Climate Change

It is one of the ways to respond to climate change, along with mitigation. It aims to reduce or avoid harm or exploit opportunities. The need for adaptation varies from place to place, depending on the vulnerability to environmental impacts. Adaptation actions can be grouped into three categories: -Structural and physical adaptation (this can be grouped into engineering and built environment, technological, ecosystem-based, services) -Social adaptation (educational, informational, behavioral) -Institutional adaptation (economic organizations, laws and regulations, government policies and programs)

The Physical Science Basis Observations

It is unequivocal that human influence has warmed the atmosphere, ocean and land. Each of the last four decades has been successively warmer than any decade that preceded it since 1850. Global surface temperature was 1.09°C higher in 2011-2020 than 1850-1900, with larger increases over land (1.59°C) than over the ocean (0.88 °C) The likely range of human-caused global temperature increase from 1850-1900 to 2010-2019 is 0.8°C to 1.3°C. It is likely that well-mixed GHGs contributed a warming of 1.0°C to 2.0°C Other human drivers (aerosols) contributed to a cooling of 0.0°C to 0.8°C Natural drivers and internal variability changed global temperature by -0.1°C to +0.1°C and by -0.2°C to +0.2°C, respectively.

What is climate change mitigation?

It refers to efforts to cut or prevent the emission of greenhouse gases - limiting the magnitude of future warming. It may also encompass attempts to remove greenhouse gases from the atmosphere. It differs from climate change adaptation, which refers to the actions taken to manage the unavoidable impacts of climate change. Mitigation may require the use of New technologies Clean energy sources Change people's behavior Make older technology more energy efficient.

Vector borne diseases

Lyme disease is the most common vector-borne disease in the United States and in recent years, infected approximately 20,000-30,000 people per (Centers for Disease Control and Prevention - CDC). It is transmitted through the bite of certain species of infected deer ticks that carry the Lyme disease bacteria. Climate change has contributed to the expanded range of ticks, such as in areas of Canada where they were previously unable to survive. Deer ticks are mostly active when temperatures are above 45˚F, and they thrive in areas with at least 85% humidity.

Action toward solutions

Making the case for action: everywhere. The share of US contribution to global GHG emissions has decreased since the 1990, from 18% to 12% of total In absolute amounts, it has increased -18% of 38 GtCO2 in 1990 equals 6.84 Gt CO2 -12% of 60 GtCO2 in 2019 equals 7.2 GtCO2 North America is the region with the highest emission per capita....by far

How do scientists validate climate models?

Models are tested by comparing them against observations over the past century. Models are not input historical temperature readings, but information on past climate forcings (GHG concentrations, aerosols) and the models generate a "hindcast" of historical conditions. Climate model hindcasts of different climate factors including temperature (across the surface, oceans and atmosphere), rain and snow, hurricane formation, sea ice extent and many other climate variables have been used to show that models are able to accurately simulate the Earth's climate.

Uncertainties in the climate system-clouds

Much more problematic are clouds -They account for most of the reflection of sunlight by our planet, thereby cooling it. -They also absorb and reradiate infrared radiation like GHG, thereby exerting a warming effect. -Which effect wins depends on the altitude and optical properties of the clouds. -At present, there is no generally accepted theory for how clouds respond to climate change. -Clouds are now considered the main source of uncertainty in climate projections.

Observed Impacts- Tropical Cyclones

Number of Atlantic Tropical Cyclone has increased since the 1980s The year of 2020 holds the record (30) for named storms (those that reach 39 mi/hr or 63 km/hr)

Impacts of Climate Change

Observable or visible changes related to human-caused climate change Included are impacts on physical environment, ecosystems and human societies. Climate Change AR6: Even with 1.1oC of global warming, impacts are already pervasive Increase in frequency and intensity of hot extremes in land and ocean, heavy precipitation and fire weather. Species extinctions have been attributed to climate change 50% of species assessed globally have shifted habitats Amplification of weather and climate events has exposed millions to acute food and water insecurity Climate change is contributing to humanitarian crises where climate hazards interact with high vulnerability

Ten solutions to bend the curve (GHG concentration)

Organized in 6 clusters Science Pathways Societal Transformation Governance Markets and Regulations Technology Measures Ecosystem Management

Under the Hood of a Climate Model

Real properties such as conservation of energy and mass must be accurately represented. Variables like air pressure, temperature and wind are expresses as equations the models must solve. This results in a 3-D picture of the natural system Models that predict weather, for example, solve a large set of equations. Although equations governing climate are precisely known, we can't model every single interaction using present day computers. The solution is to average over big blocks of space and time (gridcells), usually 100 km and 1 km thick in the vertical This averaging introduces errors and skips over important climate processes.

the community battles

Residents had petitioned local, state and federal officials to reject the permit after representatives for the pipeline company said construction through the historically Black neighborhood of Boxtown represented the "path of least resistance". The company later pulled its permit request for the project, citing low oil production caused by the pandemic. Why it matters: Justin J Pearson, one of the organizers with the Memphis pipeline campaign, says their victory shows the power of the people still holds sway.

Dealing with uncertainty

Scientists have developed different strategies to account for uncertainty and have used these to estimate a range of possible temperatures in the coming century. There are roughly 40 climate models run by different organizations around the world, and they all give somewhat different projections about the response of climate to increasing concentrations of GHG. We also have to estimate just how the GHG content of the atmosphere will evolve, which requires not just an understanding of the physics, chemistry, and biology controlling these gases but an assessment of human behavior Estimating future emissions is a problem of economic and behavioral forecasting, including predicting population growth. Recent experience shows that, as gross national product per capita expands, population growth tends to level off, ameliorating the growth in energy demand. In addition to the uncertainty surrounding the emissions, there is inherent uncertainty in the models themselves. -One strategy is to run many different models and each of them many times to produce a large ensemble of projections. -Comparing the results of the many members of such an ensemble gives us some idea of the inherent uncertainty in model projections.

Observed Impacts- oceans

Sea Level Rise Absolute sea level has risen at an average rate of 0.06 in (1.5 mm) per year from 1880 to 2019. Since 1993, however, average sea level has risen at a rate of 0.12 to 0.14 in (3 to 3.5 mm) per year—roughly twice as fast as the long-term trend. Relative sea level rose along much of the U.S. coastline between 1960 and 2020, particularly the Mid-Atlantic and parts of the Gulf coasts, where some stations registered increases of more than 8 inches

Structural and physical adaptation

Sea walls -protection against flooding and sea-level rise Damming glacial lakes In agriculture -Rainwater storage -More efficient irrigation practices -Agricultural-solar solutions -Develop varieties with greater drought tolerance Protection against heatwaves and extreme heat -Incentivize light colored and/or green roofs -Passive cooling systems - wind towers Nature-based solutions -Benefit both humans and ecosystems -Mangroves preservation - reduce storm surge -Reforestation: restore ecosystems services such as water availability

Pests

Tar spot, a fungal disease native to Latin America, which can cause up to 50% of yield losses in maize, was detected for the first time in the US in 2015. Normally prevalent in tropical climates, the disease has started emerging in non-tropical regions, including highland areas of Central Mexico and many counties in the US

The Pine Beetle epidemic

The Pine Beetle epidemic has aggressively devastating forests in all 19 Western States and Canada, effectively decimating approximately 88 million acres of timber at a 70-90% kill rate. The pine beetle is moving north as temperatures rise and is likely to spread throughout northeastern United States and into southeastern by 2050 Dead pine timber became a profitable business.....

Growing Season Length

The average length of the growing season in the contiguous 48 states has increased by more than two weeks since the beginning of the 20th century. In the West, the length of the growing season has increased at an average rate of about 2.2 days per decade since 1895, compared with a rate of nearly one day per decade in the East. States in the Southwest (e.g., Arizona and California) have seen the most dramatic increase. In contrast, the growing season has become shorter in two states: Alabama and Georgia. In recent years, the final spring frost has been occurring earlier, and the first fall frost has been arriving later. The average length of the growing season in the contiguous 48 states has increased by more than two weeks since the beginning of the 20th century. In the West, the length of the growing season has increased at an average rate of about 2.2 days per decade since 1895, compared with a rate of nearly one day per decade in the East. States in the Southwest (e.g., Arizona and California) have seen the most dramatic increase. In contrast, the growing season has become shorter in two states: Alabama and Georgia. In recent years, the final spring frost has been occurring earlier, and the first fall frost has been arriving later.

Principles, variables and parameterizations

The dynamics of the climate system are governed by the physical principles: Conservation of mass (air and water) Conservation of energy Conservation of momentum The ideal gas law applied to air This principles constrain the variables Air temperature and pressure Density Water vapor content Wind magnitude in 3 directions By solving the equations models simulate these variables in 3-dimension and in time Other important variables cannot be modeled directly. Clouds for example are much smaller than the smallest unit of a typical climate model and and their effect on temperature are taken together. This is done through parameterizations, or simplified equations that approximate the complex real process. Parameterizations are based in some assumptions and their efficacy are determined by how well they simulated past events. Rain, snow and evaporation for example are parameterized in models. Getting parameterizations correctly is an important part of designing a climate model.

How does climate change attribution work?

The frequency of an event of a certain magnitude (based on historical and observational data) is determined Having good observational data that goes back a long way is important. Some types of extreme events can be more accurately analyzed than others. Those with long observational records that can be simulated by computer models, especially those connected to temperature, such as heat waves, deliver the most certainty in attribution studies. Attribution studies then run identical climate models under two scenarios. In the first, GHG concentrations are kept constant at a level from before the Industrial Revolution. The climate model is run over ~150-year. This is called the "counterfactual world" or "control run". For the second scenario, the climate model is run over the same period with the actual GHG concentrations for each year as they increased over time. By comparing the results from the two modeled scenarios, scientists can estimate how much human emissions from fossil fuel activity have shifted the odds. Statistical methods are then used to quantify the differences in severity and frequency of the event. For example, if the extreme event occurs twice as often in today's climate model as it does in the control run, then climate change is determined to have made the event twice as likely as it would otherwise have been in a world without human-induced emissions.

Uncertainties in the climate system

There are numerous challenges when attempting to model the Earth's climate system -While there is a solid understanding of many parts, some aspects of the complex climate system is still incomplete -This introduces uncertainty into our attempts to forecast how climate will change Our incomplete understanding of water vapor in the atmosphere is one source of uncertainty in modeling climate. -As the atmosphere warms, the concentration of water vapor increases, leading to further warming (positive feedback). -But the distribution of water vapor is affected by many other variables besides temperature.

Vulnerability to Climate Change

Vulnerability Is a component of Risk Defined as the propensity or predisposition to be adversely affected by climate change It's a function of exposure, sensitivity and capacity to adapt. Exposure: the presence of people; livelihoods; species or ecosystems; environmental functions, services, and resources; infrastructure; or economic, social, or cultural assets in places that could be adversely affected. Sensitivity: the degree to which a system, population, or resource is or might be affected by hazards. Adaptive capacity: the ability of a person, asset, or system to adjust to a hazard, take advantage of new opportunities, or cope with change. Exposure Homes and businesses along low-lying coasts are exposed to coastal flooding from storms Sensitivity The yield of crops with a high sensitivity may be reduced in response to a change in daily minimum temperature during the pollination season. Adaptive capacity Increasing the diameter of culverts that channel stormwater away from assets enhances the adaptive capacity of places that face flooding from increasingly heavy rainfalls

Connecting Vulnerability to Adaptation

Vulnerability assessment provide an important additional layer of information for decision making in terms of defining adaptation and risk reduction priorities The figure on the right shows observed changes in agricultural and ecological droughts combined with a background map of vulnerability. For example, the combined information reveals that even if the agreement on the type of changes in droughts is low for North and South-East Africa, it is the high vulnerability in this region that requires urgent attention.

Attribution Science

Whenever an extreme weather or climate-related event occurs, the question to what extent it is influenced by climate change arises The science has been able to answer that for relatively simple extremes: Hot and cold extremes Extreme precipitation and drought This emerging field of climate science is called Extreme Event Attribution It aims to assess estimates of changing risks of extreme weather and climate A 2004 paper "Human Contribution to the European Heat Wave of 2003" is the first attribution science study It modeled how much human-induced greenhouse gases increased the likelihood of the historic 2003 heat wave in Europe

The history of temperature change

averaged over this region is well reproduced by simulations of the HadCM3 climate model Temperature changes is calculated from 5 simulations Four with the same combination of GHG, sulphate aerosols, changes in tropospheric and stratospheric ozone, as well as natural changes in solar output and explosive volcanic eruptions, but different initial conditions. One with natural drivers alone (solar and volcanic forcings, and denoted NAT) The summer of 2003 was out of range of modeled variability for simulations that included only natural forcings

GHG emission by geographical regions

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GHG emission by source

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covid-19 impact on emissions and opportunities for mitigation

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climate change mitigation signs of progress

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GHG emission by source 2

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Impacts and Risks

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c02 emissions taken up by land and ocean carbon sinks

is smaller in scenarios with higher cumulative co2 emissions

Climate Change Risk

lies at the intersection of: Climate Hazards The potential occurrence of a climate-related event that may cause loss of life, injury, or other health impacts, as well as damage and loss to property, infrastructure, livelihoods, service provision, ecosystems and environmental resources. Vulnerability The propensity to be adversely affected and lack of capacity to cope and adapt to climate change Exposure The presence of people; livelihoods; species or ecosystems; environmental functions, services and resources; infrastructure; or economic, social or cultural assets in places that could be adversely affected

The Physical Science Basis Projections

projected changes in extremes are longer in frequency and intensity with every additional increment of global warming Continued global warming is projected to further intensify the global water cycle, including its variability, and the severity of wet and dry events Many changes in the climate become larger in direct relation to increasing global warming. They include increases in the Frequency and intensity of hot extremes and marine heatwaves Heavy precipitation In some regions, agricultural and ecological droughts; Proportion of intense tropical cyclones; And reductions in Arctic sea ice, snow cover and permafrost. Monsoon precipitation is projected to Increase in the mid- to long term at the global scale , particularly over South and Southeast Asia, East Asia and West Africa apart from the far west Sahel (high confidence). The monsoon season is projected to have a delayed onset over North and South America and West Africa (high confidence) and a delayed retreat over West Africa (medium confidence) In the longer term, sea level is committed to rise for centuries to millennia due to continuing deep-ocean warming and ice-sheet melt and will remain elevated for thousands of years (high confidence). Over the next 2000 years, global mean sea level will rise by about 2 to 3 m if warming is limited to 1.5°C, 2 to 6 m if limited to 2°C and 19 to 22 m with 5°C of warming, and it will continue to rise over subsequent millennia (low confidence). All regions are projected to experience further increases in hot climatic impact-drivers (CIDs) and decreases in cold CIDs (high confidence). Further decreases are projected in permafrost; snow, glaciers and ice sheets; and lake and Arcticsea ice (medium to high confidence). These changes would be larger at 2°C global warming or above than at 1.5°C (high confidence). For example, extreme heat thresholds relevant to agriculture and health are projected to be exceeded more frequently at higher global warming levels (high confidence).

The Montreal Protocol

signed in 1987 to phase out ozone-depleting chemicals, was essential for the recovery of the ozone layer, prevented millions of cases of skin cancer a year and headed off even worse global warming This is an example of effective policy enacted collectively

Are Climate Models Improving?

yes

Societal Transformation step 1

1) Preparation Clear messages, repeated often, by a variety of trusted messengers. Know your audience: use examples that relate to them Learn about the most common falsehood about climate change and be prepared to refute them convincingly Facts matter. All the warmest years are in recent years. The evidence for warming is not weak. The atmosphere is warming. So is the ocean. Sea level is rising. Ice sheets and glaciers are shrinking. Rainfall patterns and severe weather are changing. Climate change is serious. It's not a remote threat for the future. It's here now.

Societal Transformation step 2

2. Stories (Myth Debunking) Question/Myth: How can you forecast climate for a century if you can't even forecast the weather for next week? Answer: Climate is statistics, and that is much more predictable than daily weather. We can skillfully forecast mortality statistics for large populations, but not the lifetime of a specific person Myth: In the 1970s, climate scientists predicted global cooling. Answer: That's simply not true. Global cooling was prominent in some media articles and popular books, but not in scientific articles Myth: the sun causes climate change. Answer: That is true, but not for the warming observed in recent decades. The effects of the sun's changes in recent decades are tiny compared with effects caused by humans. Myth: human CO2 emissions are tiny compared with natural CO2 emissions Answer: the statement ignores how nature absorbs CO2, balancing emissions Myth: CO2 is a trace gas and has a weak effect Answer: saying a small amount can't have a strong effect is wrong. Like saying an aspirin won't have an effect as it is only 3 parts per million of your weight

Societal Transformation step 3

3. Metaphors You are watching soccer. The player who is thought to be on performance-enhancing drugs scores 3 times. Did the steroids cause it? You can't be sure they caused it, because he was already a great player when he was clean. And even with the drugs, he can still have a bad performance now and then. But at the end of the season, his statistics show that he scored more goals than he used to. The drugs increased the odds of him scoring goals

Societal Transformation step 4

4. Language Be sure to use units that are familiar to your audience. Scientists use metric units, but when speaking to or writing for a non-scientific audience in the United States, metric units will be both unintelligible and frustrating to the audience. Instead, use feet, miles, pounds, degrees Fahrenheit, etc.

Societal Transformation step 5

5. Solutions When you communicate climate change science, be sure to include information on solutions. Climate change poses difficult problems and challenges, but there are lots of solutions that are both creative and practical Science can inform policy, but only concerned people and responsive, capable governments can decide what policies are best, and then implement them

the courtroom rulings-dutch court

A Dutch court handed down a landmark decision in May to force Royal Dutch Shell, one of the top 10 polluters in the world, to cut emissions by 45% before 2030. Though the court didn't find the company had broken any laws, it said Shell had endangered human lives, violating the country's civil codes. Another 2021 courtroom victory came for the 16 young plaintiffs in Held v State of Montana, a suit alleging that Montana contributed to the climate crisis and violated their constitutional rights. Why it matters: "At this political stage where our governments, both federally and in Montana, are determined to continue to rely on fossil fuels, we turn to our courts to protect [our] constitutional rights," says Grace Gibson-Snyder, 18, and one of the youth plaintiffs. "We have this opportunity to present the whole story of the government causing climate change."

Representative Concentration Pathways (RCPs)

A Representative Concentration Pathway (RCP) is a GHG concentration (not emissions) trajectory adopted by the Intergovernmental Panel for Climate Change (IPCC) Describe different climate futures depending on the volume of GHG emitted in the years to come. The RCPs are labelled after a possible range of radiative forcing values in the year 2100 (2.6, 4.5, 6, and 8.5 W/m2, respectively) RCP2.6: requires that carbon dioxide (CO2) emissions start declining by 2020 and go to zero by 2100 RCP.4.5: an intermediate scenario in which emissions in RCP 4.5 peak around 2040, then decline RCP6.0: emissions peak around 2080, then decline. RCP8.5: in RCP 8.5 emissions continue to rise throughout the 21st century