into account direct and indirect emissions, industry is the sector with the highest share of global emissions. agriculture and forestry face a triple challenge of limiting greenhouse gas emissions, preventing the further conversion of forests to agricultural land, and meeting increases in world food demand. a set of actions could reduce agriculture and forestry-based emissions by two thirds from 2010 levels. these include reducing growth in demand for food and other agricultural products, increasing land productivity, protecting and restoring forests, and reducing greenhouse gas emissions from agricultural production. on the demand side, a key component of reducing emissions is shifting people towards plant-based diets. eliminating the production of livestock for meat and dairy would eliminate about 3/4ths of all emissions from agriculture and other land use. livestock also occupy 37% of ice-free land area on earth and consume feed from the 12% of land area used for crops, driving deforestation and land degradation. steel and cement production are responsible for about 13% of industrial co2 emissions. in these industries, carbon-intensive materials such as coke and lime play an integral role in the production, so that reducing co2 emissions requires research into alternative chemistries. carbon sequestration most co2 emissions have been absorbed by carbon sinks, including plant growth, soil uptake, and ocean uptake (2020 global carbon budget). natural carbon sinks can be enhanced to sequester significantly larger amounts of co2 beyond naturally occurring levels. reforestation and tree planting on non-forest lands are among the most mature sequestration techniques, although the latter raises food security concerns. farmers can promote sequestration of carbon in soils through practices such as use of winter cover crops, reducing the intensity and frequency of tillage, and using compost and manure as soil amendments. in one of its recent publications, fao maintains that forest and landscape restoration yields many benefits for the climate, including greenhouse gas emissions sequestration and reduction. restoration/recreation of coastal wetlands, prairie plots and seagrass meadows increases the uptake of carbon into organic matter. when carbon is sequestered in soils and in organic matter such as trees, there is a risk of the carbon being re-released into the atmosphere later through changes in land use, fire, or other changes in ecosystems. where energy production or co2-intensive heavy industries continue to produce waste co2, the gas can be captured and stored instead of released to the atmosphere. although its current use is limited in scale and expensive, carbon capture and storage (ccs) may be able to play a significant role in limiting co2 emissions by mid-century. this technique, in combination with bioenergy (beccs) can result in net negative emissions: co2 is drawn from the atmosphere. it remains highly uncertain whether carbon dioxide removal techniques will be able to play a large role in limiting warming to 1.5 °c. policy decisions that rely on carbon dioxide removal increase the risk of global warming rising beyond international goals. adaptation mangrove planting and other habitat conservation can reduce coastal flooding. seawalls to protect against storm surge worsened by sea level rise green roofs to provide cooling in cities adaptation is "the process of adjustment to current or expected changes in climate and its effects".: 5 without additional mitigation, adaptation cannot avert the risk of "severe, widespread and irreversible" impacts. more severe climate change requires more transformative adaptation, which can be prohibitively expensive. the capacity and potential for humans to adapt is unevenly distributed across different regions and populations, and developing countries generally have less. the first two decades of the 21st century saw an increase in adaptive capacity in most low- and middle-income countries with improved access to basic sanitation and electricity, but progress is slow. many countries have implemented adaptation policies. however, there is a considerable gap between necessary and available finance. adaptation to sea level rise consists of avoiding at-risk areas, learning to live with increased flooding and protection. if that fails, managed retreat may be needed. there are economic barriers for tackling dangerous heat impact. avoiding strenuous work or having air conditioning is not possible for everybody. in agriculture, adaptation options include a switch to more sustainable diets, diversification, erosion control and genetic improvements for increased tolerance to a changing climate. insurance allows for risk-sharing, but is often difficult to get for people on lower incomes. education, migration and early warning systems can reduce climate vulnerability. planting mangroves or encouraging other coastal vegetation can buffer storms. ecosystems adapt to climate change, a process that can be supported by human intervention. by increasing connectivity between ecosystems, species can migrate to more favourable climate conditions. species can also be introduced to areas acquiring a favorable climate. protection and restoration of natural and semi-natural areas helps build resilience, making it easier for ecosystems to adapt. many of the actions that promote adaptation in ecosystems, also help humans adapt via ecosystem-based adaptation. for instance, restoration of natural fire regimes makes catastrophic fires less likely, and reduces human exposure. giving rivers more space allows for more water storage in the natural system, reducing flood risk. restored forest acts as a carbon sink, but planting trees in unsuitable regions can exacerbate climate impacts. there are synergies but also trade-offs between adaptation and mitigation. an example for synergy is increased food productivity which has large benefits for both adaptation and mitigation. two examples for trade-offs include: firstly, the increased use of air conditioning allows people to better cope with heat, but increases energy demand. secondly, more compact urban development may lead to reduced emissions from transport and construction which is good. but at the same time, this kind of urban development may increase the urban heat island effect, leading to higher temperatures and increased exposure of people to heat-related health risks. policies and politics the climate change performance index ranks countries by greenhouse gas emissions (40% of score), renewable energy (20%), energy use (20%), and climate policy (20%). high medium low very low countries that are most vulnerable to climate change have typically been responsible for a small share of global emissions. this raises questions about justice and fairness. climate change is strongly linked to sustainable development. limiting global warming makes it easier to achieve sustainable development goals, such as eradicating poverty and reducing inequalities. the connection is recognised in sustainable development goal 13 which is to "take urgent action to combat climate change and its impacts". the goals on food, clean water and ecosystem protection have synergies with climate mitigation. the geopolitics of climate change is complex. it has often been framed as a free-rider problem, in which all countries benefit from mitigation done by other countries, but individual countries would lose from switching to a low-carbon economy themselves. this framing has been challenged. for instance, the benefits of a coal phase-out to public health and local environments exceed the costs in almost all regions. furthermore, net importers of fossil fuels win economically from switching to clean energy, causing net exporters to face stranded assets: fossil fuels they cannot sell. policy options a wide range of policies, regulations, and laws are being used to reduce emissions. as of 2019, carbon pricing covers about 20% of global greenhouse gas emissions. carbon can be priced with carbon taxes and emissions trading systems. direct global fossil fuel subsidies reached $319 billion in 2017, and $5.2 trillion when indirect costs such as air pollution are priced in. ending these can cause a 28% reduction in global carbon emissions and a 46% reduction in air pollution deaths. money saved on fossil subsidies could be used to support the transition to clean energy instead. more direct methods to reduce greenhouse gases include vehicle efficiency standards, renewable fuel standards, and air pollution regulations on heavy industry. several countries require utilities to increase the share of renewables in power production. policy designed through the lens of climate justice tries to address human rights issues and social inequality. for instance, wealthy nations responsible for the largest share of emissions would have to pay poorer countries to adapt. as the use of fossil fuels is reduced, jobs in the sector are being lost. to achieve a just transition, these people would need to be retrained for other jobs. communities with many fossil fuel workers would need additional investments. international climate agreements since 2000, rising co2 emissions in china and the rest of world have surpassed the output of the united states and europe. per person, the united states generates co2 at a far faster rate than other primary regions. nearly all countries in the world are parties to the 1994 united nations framework convention on climate change (unfccc). the goal of the unfccc is to prevent dangerous human interference with the climate system. as stated in the convention, this requires that greenhouse gas concentrations are stabilised in the atmosphere at a level where ecosystems can adapt naturally to climate change, food production is not threatened, and economic development can be sustained. the unfccc does not itself restrict emissions but rather provides a framework for protocols that do. global emissions have risen since the unfccc was signed. its yearly conferences are the stage of global negotiations. the 1997 kyoto protocol extended the unfccc and included legally binding commitments for most developed countries to limit their emissions. during the negotiations, the g77 (representing developing countries) pushed for a mandate requiring developed countries to " the lead" in reducing their emissions, since developed countries contributed most to the accumulation of greenhouse gases in the atmosphere. per-capita emissions were also still relatively low in developing countries and developing countries would need to emit more to meet their development needs. the 2009 copenhagen accord has been widely portrayed as disappointing because of its low goals, and was rejected by poorer nations including the g77. associated parties aimed to limit the global temperature rise to below 2 °c. the accord set the goal of sending $100 billion per year to developing countries for mitigation and adaptation by 2020, and proposed the founding of the green climate fund. as of 2020, only 83.3 billion were delivered. only in 2023 the target is expected to be achieved. in 2015 all un countries negotiated the paris agreement, which aims to keep global warming well below 2.0 °c and contains an aspirational goal of keeping warming under 1.5 °c. the agreement replaced the kyoto protocol. unlike kyoto, no binding emission targets were set in the paris agreement. instead, a set of procedures was made binding. countries have to regularly set ever more ambitious goals and reevaluate these goals every five years. the paris agreement restated that developing countries must be financially supported. as of october 2021, 194 states and the european union have signed the treaty and 191 states and the eu have ratified or acceded to the agreement. the 1987 montreal protocol, an international agreement to stop emitting ozone-depleting gases, may have been more effective at curbing greenhouse gas emissions than the kyoto protocol specifically designed to do so. the 2016 kigali amendment to the montreal protocol aims to reduce the emissions of hydrofluorocarbons, a group of powerful greenhouse gases which served as a replacement for banned ozone-depleting gases. this made the montreal protocol a stronger agreement against climate change. national responses in 2019, the united kingdom parliament became the first national government to declare a climate emergency. other countries and jurisdictions followed suit. that same year, the european parliament declared a "climate and environmental emergency". the european commission presented its european green deal with the goal of making the eu carbon-neutral by 2050. major countries in asia have made similar pledges: south korea and japan have committed to become carbon-neutral by 2050, and china by 2060. in 2021, the european commission released its “fit for 55” legislation package, which contains guidelines for the car industry; all new cars on the european market must be zero-emission vehicles from 2035. while india has strong incentives for renewables, it also plans a significant expansion of coal in the country. vietnam is among very few coal-dependent fast developing countries that pledged to phase out unabated coal power by the 2040s or as soon as possible there after. as of 2021, based on information from 48 national climate plans, which represent 40% of the parties to the paris agreement, estimated total greenhouse gas emissions will be 0.5% lower compared to 2010 levels, below