Sustainability is a social goal for people to co-exist on Earth over a long time. Specific definitions of this term are disputed and have varied with literature, context, and time. Experts often describe sustainability as having three dimensions (or pillars): environmental, economic, and social, and many publications emphasize the environmental dimension. In everyday use, sustainability often focuses on countering major environmental problems, including climate change, loss of biodiversity, loss of ecosystem services, land degradation, and air and water pollution. The idea of sustainability can guide decisions at the global, national, and individual levels (e.g. sustainable living). A related concept is sustainable development, and the terms are often used to mean the same thing. UNESCO distinguishes the two like this: "Sustainability is often thought of as a long-term goal (i.e. a more sustainable world), while sustainable development refers to the many processes and pathways to achieve it."The economic dimension of sustainability is controversial. Scholars have discussed this under the concept of "weak and strong sustainability"; for example, there will always be tension between the ideas of "welfare and prosperity for all" and environmental conservation, so trade-offs are necessary. Approaches that decouple economic growth from environmental deterioration would be desirable. But they are difficult to carry out.Measuring sustainability is difficult. Indicators consider environmental, social and economic domains. The metrics are evolving. Currently, they include certification systems, types of corporate accounting, and types of index. It is necessary to address many barriers to sustainability to make a sustainability transition possible.: 34  Some barriers arise from nature and its complexity. Other barriers are extrinsic to the concept of sustainability. For example they can result from the dominant institutional frameworks in countries. There are many approaches people can take to transition to environmental sustainability. These include maintaining ecosystem services, reducing food waste, and promoting dietary shifts towards plant-based foods. Another is reducing population growth by cutting fertility rates. Others are promoting new green technologies, and adopting renewable energy sources while phasing out subsidies to fossil fuels. The United Nations agreed the Sustainable Development Goals (SDGs) in 2015. These set a global agenda for sustainable development, with a deadline of 2030. One of many ways to overcome barriers to sustainable development is to decouple economic growth from environmental conservation. This means using fewer resources per unit of output even while growing the economy. This reduces the environmental impact of economic growth such as pollution. Doing this is difficult. Some experts say there is no evidence that it is happening at the required scale. Global issues are difficult to tackle as they need global solutions. Existing global organizations such as the UN and WTO are inefficient in enforcing current global regulations. One reason for this is the lack of suitable sanctioning mechanisms.: 135–145  Governments are not the only sources of action for sustainability. Business groups have tried to integrate ecological concerns with economic activity. Religious leaders have stressed the need for caring for nature and environmental stability. Individuals can also live in a more sustainable way.The concept of sustainability has faced various criticisms. One is that the concept is vague and only a buzzword. Another is that sustainability might be an impossible goal. Some experts have pointed out that "no country is delivering what its citizens need without transgressing the biophysical planetary boundaries".: 11  Source: Wikipedia (en)