Purpose: This guide sets out to answer whether modern tools and platforms can protect natural systems while acknowledging their current impact on global resources and greenhouse gas emissions. It combines clear data, practical ways forward and evidence-based trends to inform action.
Brief data matter. The sector accounts for a notable share of greenhouse gas emissions, with data centres using vast amounts of electricity and e-waste rising to record levels. A smartphone’s manufacture drives much of its carbon and water footprint.
Dual narrative: platforms and smart grids drive decarbonisation through falling costs, AI-enabled optimisation and system integration, yet resource extraction, water use and device lifecycles still pose major challenges.
What follows: lifecycle impacts first, then solution pathways across renewables, storage, AI for grids, circular supply chains and policy levers. This guide relies on transparent data, case studies and actionable content to move beyond hype towards real sustainability.
Why this Ultimate Guide matters: technology’s growing climate impact and opportunity
Numbers from recent reports make plain why a focused guide is overdue. The sector now accounts for an estimated 2–7% of global greenhouse gas emissions and uses roughly 6–12% of global energy across data centres, workplace devices and ICT networks.
Big Tech firms alone were near 4% of global emissions in 2023. Manufacturing drives most device footprints: about 80% for smartphones. Full production and assembly use about 12,760 litres of water per handset when mining is included.
Why this guide is timely: digital services, cloud platforms and connected devices are rising fast while clean solutions mature. That creates space for rapid gains — and fresh risks.
- Opportunity: falling costs for renewable power and storage, AI‑driven efficiency and smarter grids that cut waste and accelerate decarbonisation.
- Persistent challenges: growing demand, tens of millions of tonnes of e‑waste annually, and recycling rates stuck near 17–20%.
- Corporate action: firms need clear targets, credible procurement and transparent reporting to align growth with climate change goals.
This Ultimate Guide curates report‑grade data and practical content to help readers interpret complex datasets and choose high‑impact next steps.
Understanding technology’s dual impact on the environment
Modern devices trace a long path from mines to landfill, with measurable effects at each stage.
From extraction to disposal: lifecycle realities of modern tech
Map the life of a device: raw material extraction, refining, manufacture, logistics, use and end‑of‑life. Each stage shifts burden between regions and people.
Mining for electronics destroys habitat and pollutes local water and soil. Hazardous materials such as lead, mercury, cadmium and arsenic remain in many devices.
Balancing innovation, efficiency, and unintended consequences
Production dominates carbon and water footprints. A smartphone can require about 12,760 litres of water, and roughly 80% of its carbon arises during production.
“Efficient design must avoid burden‑shifting: lower use‑phase energy does not excuse poor material choices upstream.”
Lifecycle stage | Main impacts | Typical hotspots |
---|---|---|
Extraction | Habitat loss, pollution | Mining sites, freshwater |
Production | Carbon, water use | Factories, assembly lines |
End‑of‑life | Waste, toxic release | Informal recycling, dumps |
Lifecycle assessment (LCA) offers a tool to spot hotspots and avoid shifting harm between stages or places. Policymakers and firms must weigh efficiency gains against rebound effects, as cheaper, faster gear often drives higher absolute consumption.
Innovation is a balancing act: pursue performance and miniaturisation while cutting embodied carbon, water and waste across every phase of product life.
Quantifying the footprint: energy, carbon, water, and e-waste in today’s tech
A precise accounting of power, carbon and e‑waste shows which interventions yield real gains.
ICT emissions and energy use: data centres, networks, and devices
Data centres, networks and end devices draw a rising share of global power. Estimates place ICT at about 4% of global greenhouse gas emissions and 6–12% of global energy use.
Data centres alone consume roughly 70 billion kWh annually. The international ICT sector emits ~730 million tonnes of CO2 each year — a footprint similar to aviation in scale.
Operational choices matter: workload scheduling, site selection and procurement reduce absolute energy and gas-related emissions when paired with cleaner grid supply.
E-waste trends, recycling rates, and hazardous materials
Global e-waste generation now sits near 53.6–57.4 million tonnes yearly. Formal recycling rates remain low, about 17–20%.
- Regional gaps are large: high-income markets generate most per-capita waste while low-income regions face informal processing shortfalls.
- Devices contain hazardous substances such as lead and mercury that create health risks when informal recycling or landfill disposal occurs.
- Water use is concentrated in semiconductor and handset manufacture; process changes and supply-chain choices cut embodied water and carbon.
Key market opportunity: higher collection, improved sorting and high-yield recovery address a clear material and public-health gap while reducing lifecycle impact.
Can technology help the environment: defining the pathways to sustainability
Falling costs for renewables and storage unlock scalable, investable routes to decarbonisation.
Sustainability becomes a systems outcome when devices, software and infrastructure align with science‑based targets.
Principal pathways include clean power, electrification, circularity, efficiency and digital optimisation. Each path reduces resource use and lowers emissions when paired with strong policy and finance.
- Clean power: rapid solar, wind and storage deployment driven by falling costs and grid additions forecast to get cheaper by 15–20% to 2030.
- Electrification: shifting transport and heating to low‑carbon electricity reduces fossil fuel demand.
- Circularity: design for repair, reuse and high‑yield recycling cuts embodied waste.
- Efficiency and digital optimisation: smarter operations minimise waste and boost asset utilisation.
Standards, transparency and credible accounting translate intent into measurable impact across markets and around world. Clear metrics guard against greenwash and allow investors to back bankable solutions.
Behavioural change and demand‑side measures complement innovation to limit rebound effects. Digital tools then orchestrate assets, verify results and reduce material loss across supply chains.
Renewable power breakthroughs: solar cost declines and efficiency gains
Solar innovation has shifted from lab curiosity to one of most cost-competitive forms of power worldwide.
Wright’s law explains decades of steady falls in unit costs: across ~40 years, each doubling of global capacity drove roughly 20% lower price. That learning curve, paired with China supplying up to 80% of global panels, pushed module prices from USD 0.21/W in April 2023 to USD 0.11/W by April 2024. These moves changed investment calculus in many markets.
Cell efficiency and materials progress
Monocrystalline silicon historically delivered 15–24% conversion rates. Tandem perovskite–silicon stacks now reach 34.6% — a Longi record — closing in on theoretical limits near 43%.
Higher conversion means smaller arrays, less material use and lower embodied carbon per kWh. That improves carbon abatement per pound invested and trims system LCOE when balance-of-system and soft costs fall in step.
Flexible films and integrated generation
Oxford researchers developed thin, flexible power‑generating materials suitable for building envelopes, vehicles and devices. These forms extend generation beyond fixed panels and open new deployment patterns for urban sites.
Metric | Recent value | Impact |
---|---|---|
Module price (Apr 2024) | USD 0.11/W | Reduces upfront equipment costs |
Longi tandem efficiency | 34.6% | Smaller arrays, lower embodied carbon/kWh |
China market share | ~80% | Scale drives rapid costs falls |
Learning rate | ~20% per doubling | Predictable long‑term cost declines |
- Near‑term trends: bankability, durability tests, and supply assurance will shape mainstream adoption across world markets.
- Efficiency gains reduce materials and lower lifecycle carbon while supporting faster rise in deployed capacity.
Wind power advances: from onshore workhorses to floating offshore farms
Wind power has shifted from simple rotors to engineered systems that capture far more energy per sweep.
Higher capture and smarter design: modern turbines extract up to 50% of wind passing through rotors, versus about 22% before 1998. Better aerodynamics and stronger drivetrains raise capacity factors across both onshore and offshore fleets.
Higher capacity extraction and cost curves to 2030
US DOE analysis suggests science and technology breakthroughs could halve delivered costs by 2030. Lower costs widen market access and unlock sites previously marginal due to distance or depth.
Recyclable blades and plant-based materials
Most turbine mass — steel, aluminium, copper — is 85–95% recyclable. Work on plant‑based resins and second‑life composite reuse is reducing embodied impact and waste.
Area | Recent data | Implication |
---|---|---|
Rotor capture | Up to 50% | Higher output per unit swept area |
Cost outlook | ~50% cut by 2030 (DOE) | Broader market penetration |
Materials | 85–95% recyclable | Lower lifecycle burden |
Floating farms reach steadier, higher wind speeds far from shore. Ørsted’s large Taiwan projects illustrate this global trend and show how deep‑water sites boost yield while easing coastal constraints.
Practical notes: siting, grid connection, air and acoustic impacts require careful planning. Community engagement and biodiversity safeguards are essential.
“Rooftop and motionless turbine concepts offer an example of complementary tech for evening and winter supply.”
Storage, batteries, and electric vehicles: enabling a low-carbon energy system
Energy storage is moving centre-stage in plans to electrify transport and heat. Storage balances variable renewables and keeps power reliable as electricity demand rises.
Next-generation chemistries on the rise
Solid-state cells promise higher energy density, faster charging and improved safety, with 2024 steps toward commercialisation.
Alternatives include sulphur-based, iron-air and flow batteries. Each differs in cycle life, safety and total costs.
Recycling critical materials
New processes recover nearly all cobalt and nickel, up to 100% aluminium and about 98% lithium. High recovery cuts upstream extraction, lowers waste and eases production constraints on battery supply chains.
EV adoption, charging and grid integration
China held about 76% of global EV market share in 2024. Ultra-fast charging, exemplified by Zeekr’s 10–80% in ~10.5 minutes, shifts consumer expectations and strains local grids without smart load management.
Chemistry | Energy density | Cycle life | Safety / costs |
---|---|---|---|
Solid-state | High | Good | Improved safety, higher near-term costs |
Flow | Modest | Very high | Low degradation, lower system costs for long duration |
Sulphur / iron-air | Variable | Moderate | Low materials cost, development stage |
Example roadmap for fleets: depot charging with managed schedules, V2G trials to provide grid services, and a closed-loop recovery plan for end-of-life packs.
“Electrification plus smart charging offers a practical route to reduce carbon footprint for fleets and consumers.”
AI, data, and smart grids: cutting waste, boosting efficiency, stabilising power
Smart use of algorithms and live measurements is reshaping how grids carry and share electricity.
Artificial intelligence and high‑frequency data feeds improve situational awareness. Operators gain better forecasts, faster dispatch and clearer fault detection. This raises overall efficiency while lowering losses.
Dynamic line ratings and advanced flow control
AI models compute real‑time line capacity using weather and loading inputs. Advanced power flow control shifts loads to underused conductors, increasing usable power without new builds.
Topology optimisation and demand prediction
Optimisation software redesigns network paths to cut congestion and reduce losses. Demand prediction tools smooth dispatch, speed interconnection, and raise hosting capacity for distributed assets.
Managing intermittency and curtailment
Combined analytics, forecasting and control reduce curtailment of renewables and allow higher renewable penetration. Integration of storage and distributed energy resources becomes more reliable.
Risks and rollout: cyber resilience and interoperability must be planned. Workforce change needs training to match new skills across the world.
KPI | Typical target | Impact |
---|---|---|
Reduced losses | 2–6% drop | Lower operational waste |
Hosting capacity | +15–40% | More renewables accepted |
Interconnection time | 30–60% faster | Quicker project delivery |
Curtailment | 20–70% lower | Higher yield from plants |
AI for nature: monitoring biodiversity, forests, and carbon stocks
AI models turn diverse nature datasets into clear actions for restoration and carbon accounting. Satellite imagery, aerial LiDAR and field samples feed unified analysis that flags canopy health, carbon density and habitat links across landscapes.
Drones, satellite data, and gravity-assisted tree planting
Seedpods’ 3D‑printed drone, Leonardo, drops one‑year‑old saplings inside biodegradable capsules. Three drones working together plant about 10,000 seedlings per day.
Satellite-derived maps and proprietary navigation select sites for growth potential and carbon sequestration. This example shows how aerial delivery scales restoration while targeting high‑impact locations.
eDNA, mycorrhizal mapping, and restoration planning
Environmental DNA sampling detects species from water, soil or sediment. Results reveal presence and richness and help prioritise conservation actions and track progress over time.
SPUN maps mycorrhizal fungal networks to estimate below‑ground biodiversity and stored carbon often missed by surface surveys. Combining these datasets refines species mix, spacing and maintenance plans.
- Transforms monitoring: AI and sensing technologies link canopy, soil and species data into actionable maps.
- Scalable planting: drone throughput plus satellite guidance raises restoration speed and precision.
- Informed priorities: eDNA and mycorrhizal mapping target sites with greatest ecological return.
“Digital tools, used with local knowledge, improve outcomes while respecting community rights.”
Tool | Primary use | Impact |
---|---|---|
Satellite imagery | Site selection, canopy health | Better location targeting for growth |
Seedpods Leonardo | Gravity‑assisted planting | ~10,000 seedlings/day (3 drones) |
eDNA sampling | Species detection | Prioritises conservation actions |
SPUN mapping | Mycorrhizal networks, soil carbon | Reveals below‑ground biodiversity |
Ethics and stewardship matter. Engage local communities, ensure data governance and avoid displacement of traditional practice. When applied with care, digital tools deliver robust, durable restoration solutions that boost carbon stocks, biodiversity and social value across the world.
Circular economy in tech: design, repair, remanufacture, and recycling
Design, repair and reuse form the practical backbone of a circular approach for modern devices. Global e-waste now exceeds 50 million tonnes annually, yet formal recycling rates sit near 17–20%. Smartphones alone generate about 80% of lifetime emissions during production, so extending life yields big gains.
Extending device life and cutting embodied carbon
Extending device life and cutting embodied carbon
Design-for-repair, modular parts and durable components lower production-phase emissions and reduce demand for new raw materials. Repair programmes and certified refurbishment lengthen useful service and retain value.
Scaling e-waste collection, sorting, and high-yield recovery
Raising collection and sorting capacity is essential to boost recovery rates and cut leakage to informal channels. High-yield processes reclaim cobalt, nickel and lithium and feed them back into supply chains.
- Formal collection: convenient drop-off points, trade-in schemes and urban take-back increase capture.
- Advanced sorting: automated separation and chemical recycling raise metal yields.
- Remanufacture: refurbishment preserves function while lowering materials input and waste.
Market barriers: costs, incentives, and virgin material competition
Markets still favour cheap virgin inputs when commodity prices fall. Uneven incentives, high upfront costs for recycling plants and uncertain returns slow scale-up.
“Procurement rules and credits for recovered content shift investment toward circular supply chains.”
Area | Current status | Potential impact |
---|---|---|
E-waste generation | >50 million tonnes/year | Large material pool for recovery |
Formal recycling rate | 17–20% | Major room for improvement |
Smartphone production share | ~80% lifecycle emissions | Repair increases emission savings |
Recovered materials | Cobalt, nickel, lithium, aluminium | Reduces reliance on virgin supply |
Policy and market levers — extended producer responsibility, recycled-content mandates and public procurement for refurbished units — make circular outcomes bankable. Measurable gains show up in lower production emissions, stronger resource security and improved supply resilience.
Risks, rebound effects, and the problem of solutionism
Efficiency gains often shrink unit costs but can expand total demand, creating hidden increases in resource use. That dynamic—known as rebound—means apparent savings sometimes produce higher aggregate impact.
Behavioural change and demand-side efficiency
Solutionism describes overreliance on tools while ignoring social and structural levers. This risks overlooking policy, norms and incentives needed for durable change.
Rebound appears in streaming, cloud storage and fast device refresh cycles. Better efficiency lowers friction and raises use, inflating lifecycle footprints and waste.
- Practical actions: defaults that limit background sync, clear storage quotas and slower upgrade paths reduce needless consumption.
- Service design: nudges, transparent metrics and thrift modes align user choices with lower impact without cutting quality of life.
Measure savings carefully. Attribution must avoid double counting across suppliers, users and grid effects. Use conservative baselines and independent verification.
“Pair technical gains with demand measures to lock in real climate benefit.”
Risk | Example | Mitigation |
---|---|---|
Rebound | Higher streaming hours after better compressors | Default limits, metering |
Solutionism | Deploying gadgets without policy change | Integrate incentives, regulations |
Attribution error | Double counted grid savings | Third‑party audits, clear baselines |
Policy, markets, and finance: accelerating clean technology adoption
Front‑loaded capital and predictable policy timelines unlock faster adoption of clean solutions. To limit warming to 1.5°C, annual global energy investment must reach about USD 4.5 trillion by 2030. A 2024 report noted investment exceeded USD 3 trillion for the first time, with roughly USD 2 trillion flowing to clean technologies and infrastructure.
Despite gains, a clear finance gap remains. Faster deployment needs capital up front, matched to multi‑year procurement and regulatory roadmaps. That front‑loading lowers long‑run costs and speeds rollout.
Investment shortfall and why timing matters
Private and public funds must cover a persistent gap to 2030. Early capital reduces risk, attracts follow‑on investment and shortens payback time. Without this, many projects fail to reach scale.
Policy levers that shift markets
Standards, carbon pricing and mandatory disclosure change asset valuations and tilt the market toward lower‑emission choices. Procurement rules, tax credits and loan guarantees de‑risk adoption for households and firms.
Data centres: a high‑impact example
Efficiency rules for data centres cut operational loads and associated greenhouse gas emissions and gas usage. Strong rules plus transparent reporting make energy savings verifiable and investable.
- Why it matters: dependable regulation and credible reporting scale capital flows into clean power, storage and enabling technology.
- Policy mix: standards + pricing + disclosure unlock private capital and lower total cost of ownership over time.
“Clear rules, timely finance and measurable outcomes turn potential into projects that last.”
Global landscape: where countries lead in technologies and sustainability
Nation-level choices shape supply chains, market momentum and carbon outcomes. Policy, industrial strategy and investment patterns determine which regions scale fast and which lag. This section maps leadership across major markets and highlights risks from concentrated supply.
Regional leadership snapshot
- United States: leads in software, digital platforms and grid optimisation services. Strong venture finance fuels AI and platform solutions that raise system efficiency.
- China: scales manufacturing for solar panels and EVs. Up to 80% share in panel supply has driven rapid global price falls and large EV fleet deployment.
- Europe: advances circular design, strict standards and sustainable manufacturing rules. Rules on recycled content and extended producer responsibility push higher recovery rates.
- Asia‑Pacific (APAC): growing offshore wind projects, such as Ørsted’s Taiwan farms, show how region-level rollout can boost power supply and jobs.
Export-led manufacturing concentrates critical components. That lowers costs but raises geopolitical and supply risks. National procurement, standards alignment and targeted finance steer where production locates and how fast low‑carbon options scale.
Region | Core strength | Impact on carbon and markets |
---|---|---|
United States | Software, platforms | Faster grid optimisation, service exports, higher efficiency gains |
China | Manufacturing scale, EVs | Lower equipment costs, rapid deployment, supply concentration risk |
Europe | Circular policy, standards | Higher recycling rates, durable goods, tighter product rules |
APAC | Offshore wind, deployment | Rising power supply, regional jobs, grid upgrade demand |
Collaboration and risk mitigation
Aligning standards, sharing open data and coordinating finance unlocks faster diffusion of best practice across countries. Diversifying supply chains for critical materials builds resilience while preserving market access for emerging low‑carbon assets.
Corporate roadmaps: from net-zero IT to sustainable product design
Clear roadmaps align procurement, design and operations so companies meet measurable sustainability goals. Only about 6% of organisations report highly mature sustainable IT strategies with firm timelines, while 89% recycle under 10% of hardware.
Setting targets for ICT emissions, e-waste, and water
Start with auditable baselines across scopes and product categories. Track energy, lifecycle carbon and embodied water in devices, noting that handset manufacture often accounts for ~80% of lifecycle emissions and uses ~12,760 litres per unit.
Procurement, materials, and supply chain transparency
Define tender criteria that favour renewable electricity, low-carbon manufacture and recycled content. Require supplier take-back, certified processing and public reporting to lift effective recycling rate and cut overall waste.
Practical checklist:
- Set auditable ICT emissions targets and verify with third-party data.
- Prioritise low-embodied-carbon materials and repairable designs.
- Mandate supplier recovery schemes and certified recyclers.
- Embed sustainability across warranties and after-sales to extend life.
Action | Metric | Short-term target |
---|---|---|
Emissions reporting | Scopes 1–3 coverage | Full coverage within 24 months |
Recycling programme | Hardware recovery rate | Raise to >40% within 3 years |
Design criteria | Recycled content & repairability | Specify >30% recycled content |
Consumer actions: practical ways to reduce your digital carbon footprint
Every search, stream and sync leaves a trace. Small adjustments at device and household level offer clear, measurable gains that add up across millions of users.
Use‑phase efficiency, repair, and responsible upgrades
Use less power: enable power management, lower screen brightness and stop unnecessary background apps to cut energy draw. Each internet search emits about 0.2 g CO2, and streaming accounts for over 300 million tonnes of CO2 annually, so behaviour matters.
Extend device life: repair batteries, replace parts and delay upgrades where possible. Embodied impacts from production are high, so one extra year of life reduces lifetime emissions.
Recycling, trade‑ins, and certified e‑waste channels
Only 17–20% of e‑waste is recycled formally and 89% of organisations recycle under 10% of IT hardware. Use certified take‑back, secure trade‑ins and accredited recyclers to keep devices out of informal streams and reduce waste.
Action | Why it matters | Quick tip |
---|---|---|
Power management | Reduces running energy | Auto‑sleep after 5–10 mins |
Repair | Defers embodied emissions | Certified repair shops |
Certified recycling | Higher material recovery | Use take‑back schemes |
Household checklist — an example: stream at SD or lower when fine, schedule updates at night, batch uploads, avoid constant cloud sync, and only replace devices when performance drops or repairs fail.
Small changes at scale matter: default settings and shared practices shape demand and drive lasting change. For practical guidance, read how to reduce your digital carbon footprint.
Measuring progress: metrics that matter for technology’s environmental impact
Clear metrics turn ambition into measurable reductions across systems and supply chains. Good indicators show where to invest, how to set targets and when to change course.
Energy intensity, lifecycle carbon, and recycling rates
Start with core KPIs: energy intensity per workload, lifecycle carbon per device, recycling rate per product line and absolute emissions trajectories. Use an auditable baseline so progress is comparable over time.
Define measurement boundaries carefully. Avoid double counting across vendors, clouds and user devices by assigning scope and ownership for each emission source. That keeps reports conservative and credible.
- Benchmark: compare to peers and world leaders to set realistic glide paths.
- Procurement link: align tenders to KPI thresholds so design and purchase choices reduce greenhouse gas emissions.
- Data governance: centralise measurement rules, timestamps and units for accurate, repeatable reporting.
Metric | Target | Why it matters |
---|---|---|
Energy intensity | Reduce 20% per year | Improves operational efficiency |
Lifecycle carbon | Cut embodied CO2 by 30% | Addresses manufacture-heavy impacts (smartphone ~80%) |
Recycling rate | Raise to >40% | Unlocks material reuse from >50 Mt e-waste |
“ICT now drives roughly 4% of global greenhouse gas emissions; reliable metrics turn that fact into manageable targets.”
What’s next: trends to watch through 2030 and beyond
A steady fall in capital costs, combined with integrated asset control, sets the stage for faster generation roll‑out.
Cost decline, scale and deployment
S&P Global expects a further 15–20% drop in average costs for clean energy grid additions by 2030. That decline lowers barriers and speeds market entry for large projects.
Persistent scale‑up of manufacture reduces unit price and shortens payback. This drives a steady rise in installed capacity and real progress toward lower carbon grids.
AI-enabled optimisation and grid intelligence
Artificial intelligence tools — dynamic line ratings, power flow control and topology optimisation — expand hosting capacity for renewables. Smarter dispatch cuts curtailment and lowers system costs.
Maturing hardware and systems integration
Watch solid‑state batteries, perovskite tandem PV and floating wind. Milestones such as commercial pilots, safety certification and durable lifetimes signal readiness.
- Trends: persistent cost declines, scale manufacture and digitised planning.
- Integration: interoperability across power, mobility and buildings will unlock higher utilisation.
- Limits: science and engineering constraints remain, but learning curves and deployment rise can overcome many barriers.
“Systems integration, not isolated upgrades, will determine how much renewable generation reaches users.”
For strategic foresight, review Canada’s tech future report.
Conclusion
Practical steps taken now will determine if industrial-scale gains become lasting carbon and waste reductions. This guide finds that, with smart policy, targeted investment and steady execution, modern tools deliver high-impact solutions for climate change.
Clean costs fall across solar, wind, batteries, grids and EVs, yet annual investment must rise toward USD 4.5 trillion by 2030 to align with 1.5°C. At the same time, ICT remains a notable contributor: production-heavy device emissions, rising data-centre gas use and low formal recycling (~17–20%) demand attention to materials, production, water stewardship and waste pathways.
Time-bound targets and day-to-day action translate ambition into measurable carbon and gas reductions. Individuals, firms and countries should use the science and knowledge here to set clear levels, track progress and fund scalable solutions.
Close the loop: align power, energy, digital services and circularity so tech becomes a net contributor to planetary wellbeing over coming years. That systems view turns cost declines and innovation into durable market progress for a fairer world.