Na­ture un­der as­sault: Key in­di­ca­tors

Gulf News - - World -

Pop­u­la­tions crash­ing

From 1970 to 2014, the num­ber of an­i­mals with a back­bone — birds, rep­tiles, am­phib­ians, mam­mals and fish — plum­meted across the globe, on av­er­age, by about 60 per cent. For fresh­wa­ter ver­te­brates, losses topped 80 per cent.

Ge­o­graph­i­cally, South and Cen­tral Amer­ica have been hit hard­est, with 89 per cent less wildlife in 2014 than in 1970.

The WWF Liv­ing Planet Index tracks more than 4,000 species spread across nearly 17,000 pop­u­la­tions.

Species dis­ap­pear­ing

The index of ex­tinc­tion risk for five ma­jor groups — birds, mam­mals, am­phib­ians, co­rals and an an­cient fam­ily of plants called cy­cads — shows an ac­cel­er­at­ing slide to­wards obliv­ion.

De­pend­ing on which cat­e­gories are in­cluded, the cur­rent rate at which species are go­ing ex­tinct is 100 to 1,000 times greater than only a few cen­turies ago, when hu­man ac­tiv­ity be­gan to al­ter the planet’s bi­ol­ogy and chem­istry in earnest. By def­i­ni­tion, this means that Earth has en­tered a mass ex­tinc­tion event, only the sixth in half-a-bil­lion years.

Bound­aries breached

In 2009, sci­en­tists weighed the im­pact of hu­man­ity’s ex­pand­ing ap­petites on nine pro­cesses — known as Earth sys­tems — within na­ture. Each has a crit­i­cal thresh­old, the up­per limit of a “safe op­er­at­ing space” for our species.

The do-not-cross red line for cli­mate change, for ex­am­ple, is global warm­ing of 1.5 de­grees Cel­sius, ac­cord­ing to a new UN re­port.

So far, we have clearly breached two of these so-called plan­e­tary bound­aries: species loss, and im­bal­ances in Earth’s nat­u­ral cy­cles of ni­tro­gen and phos­pho­rous (mainly due to fer­tiliser use).

For two oth­ers, cli­mate and land degra­da­tion, we have one foot in the red zone. Ocean acid­i­fi­ca­tion and fresh­wa­ter sup­ply are not far be­hind. As for new chem­i­cal pol­lu­tants such as en­docrine dis­rup­tors, heavy met­als, and plas­tics, we sim­ply don’t know yet how much is too much.

More gen­er­ally, the mar­ginal ca­pac­ity of Earth’s ecosys­tems to re­new them­selves has been far out­stripped by hu­man­ity’s eco­log­i­cal foot­print, which has nearly tripled in 50 years.

Forests shrink­ing

Nearly 20 per cent of the Amazon rain­for­est, the world’s largest, has dis­ap­peared in five decades. Trop­i­cal de­for­esta­tion con­tin­ues un­abated, mainly to make way for soy beans, palm oil and cat­tle.

Glob­ally, be­tween 2000 and 2014, the world lost 920,000 square kilo­me­tres of in­tact or “min­i­mally dis­turbed” for­est, an area roughly the size of Pak­istan or France and Ger­many com­bined. Satel­lite data shows the pace of that degra­da­tion picked up by 20 per­cent from 2014 to 2016, com­pared with the pre­vi­ous 15 years.

Oceans de­pleted

Since 1950, our species has ex­tracted six bil­lion tonnes of fish, crus­taceans, clams, squids and other edi­ble sea crea­tures. De­spite the de­ploy­ment of in­creas­ingly so­phis­ti­cated fish­ing tech­nolo­gies, global catches — 80 per cent by in­dus­trial fleets — peaked in 1996 and have been de­clin­ing since.

Cli­mate change and pol­lu­tion have killed off half of the world’s shal­low wa­ter coral reefs, which sup­port more than a quar­ter of ma­rine life. Even if hu­man­ity man­ages to cap global warm­ing at 1.5C — which many sci­en­tists doubt is pos­si­ble — coral mor­tal­ity will likely be 70 to 90 per cent.

Coastal man­grove forests, which pro­tect against storm surges made worse by ris­ing seas, have also de­clined by up to half over the last 50 years.

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